Lobelia: is lobelia toxic?

by Paul Bergner

Medical Herbalism 10(1-2):1,15

Lobelia inflata was one of the most-often prescribed medicinal herbs both in North America and in Great Britain during the nineteenth century. It was used by all schools of medicine, but by none more so than the Thomsonian herbalists in North America, the Coffinites in Britain, and by their physician successors of the Physiomedicalist school. During the warfare between the medical sects in that century, lobelia became a symbol. To the herbalists it was a harmless herb, one of their greatest healers, and their best alternative to the extensive bloodletting and administration of mercury-derived medicines that then dominated standard medicine. To their competitors of the Regular school of medicine, lobelia was a deadly poison. The latter claim was used to justify licensing laws and in some states laws to forbid the use of lobelia or even giving it to another. Unsubstantiated and unreferenced claims of lobelia toxicity entered the medical literature of the Regulars in 1810, on the basis of selective testimony in the trial of Samuel Thomson for allegedly causing the death of Ezra Lovett the year before. Those claims have been copied and cited uncritically ever since, and remain in segments of the medical literature today as proof of prejudice and poor scholarship by their authors. In this issue, we attempt to tell the whole story, from its beginning through the present day. Our series of articles includes a literature review on lobelia toxicity, from 1809 to the present, which follows below. We also cover the trial of Samuel Thomson and the conflicting accounts of the death of Ezra Lovett, which remains the only case of alleged lobelia toxicity to provide details of dose, treatment, and symptoms, and we attempt to ascertain the cause of his death in the light of modern medical knowledge. We also cover a brief flurry of lobelia toxicity allegations in London during the early 1850s. The series of articles, although covering historical and legal subjects, contains much information about the clinical use of lobelia and about social divisions and prejudices in medical care which persist today.

Lobelia toxicity: A literature review

by Paul Bergner

Medical Herbalism 10(1-2);15-26

Lobelia inflata was introduced into medical usage in North America by the herbalist Samuel Thomson in the early nineteenth century. Subsequently, Thomson and millions of medical professionals, lay herbalists, and patients who later followed his medical theories, used lobelia freely as an emetic, antispasmodic, asthma treatment, and childbirth aid without regard for potential toxicity (Griggs, Thomson 1831; Colby; Cook). Thompsonian practitioners and their patients viewed Thomsonian herbalism as an alternative to conventional medicine of the day, which employed bloodletting and poisonous mercury preparations as its chief methods. by 1840, perhaps one-fifth of the population of the United States used Thomsonian herbalism, including the unrestricted use of lobelia, as their primary care medicine (Thomson; Griggs). The movement crossed the Atlantic to England during the late 1830s, spread among the working classes, and gave birth there to the profession of “medical botanist.” Lobelia is still in use in that country today by medical herbalists. The Thomsonian movement declined among the public in both North America and England by the 1860s, probably in response to the abandonment of bloodletting and mercurials by conventional medicine (Griggs). The use of lobelia survived among some branches of the medical profession. At least one medical school in the United States (The Physiomedicalist Institute in Chicago) taught the use of lobelia in unrestricted doses without regard for toxicity as recently as 1910. Lobelia was listed as an official medicine — as a treatment for asthma — in the first United States Pharmacopoeia in 1820, and remained official in the U.S.P. until 1920. Medical doctors of the Eclectic school used it as an antispasmodic emetic and childbirth aid at least through the 1940s.The plant’s medicinal action and potential toxicity is attributed to its content of the alkaloid lobeline, present at between 0.26 and 0.40 % in the plant. Lobeline hydrochloride was used as an emergency respiratory stimulant in intravenous, intramuscular, and subcutaneous doses by conventional physicians in the U.S. beginning in 1938 (Osol and Farrar). This use was still listed in pharmacology texts as recently as 1971 (Gisvold and Doerge). Lobeline sulfate for oral use was sold without prescription in the U.S. as recently as 1990 as a smoking deterrent (Anonymous, 1990)).

Literature on lobelia toxicity is curiously split, with standard toxicology references failing to mention it, but the textbooks of conventional medicine asserting that lobelia and/or lobeline are potentially deadly poisons. Neither is mentioned at all in the encyclopedic ten-volume Comprehensive Toxicology (Sipes et al. 1997), or in such standard works on plant toxicology as Harbourne and Baxter’s Plant Toxicology, or Toxicology of Plant and Fungal Compounds by Keeler and Tu. Table 1 shows a listing of standard references in plant safety, pharmacology, or toxicology which either fail to mention lobelia and lobeline at all, or which describe them but make no mention of potential toxicity beyond lobelia’s emetic properties. The author was unable to find any listing of toxicity for lobelia in the toxicology section of the science library at University of Colorado in Boulder in a search during the summer of 1998.

Table 1

Standard toxicology references which fail to mention lobelia toxicity

Basic Pharmacology in Medicine, (DiPalma and DiGregori)

Botanical Safety Handbook (McGuffin et al.)

The Colour Atlas of Poisonous Plants: A Handbook for Pharmacists, Doctors, Toxicologists, and Biologists (Frohne and Pfänder)

Comprehensive Toxicology (Sipes et al., 1997)

De Re Medicina: Editio Secunda, published by the Eli Lilly Company in 1941

Dictionary of Plant Toxins (Harbourne and Baxter)

Handbook of Toxic and Hazardous Chemicals and Carcinogens (Sittig)

Merck Index (edition) (Budavari et al.)

Natural Product Medicine (Der Marderosian and Liberti)

Toxicology of Plant and Fungal Compounds (Keeler and Tu)

Toxicology, The Basic Science of Poisons (Casarett and Doull)

Even the American Medical Association’s AMA Handbook of Poisonous and Injurious Plants (Lamps and McCann) fails to mention serious side effects to lobelia, although the statement that symptoms are similar to those produced by nicotine (“but usually more transient”) might be taken as an assertion of toxicity, as nicotine is a strong poison. No reference is made to any deaths that may have occurred or to a lowest fatal dose.

Tyler asserts that lobelia is toxic in strong terms (“the ratio of risk to benefit is very high”) in his Herbs of Choice (Tyler 1994), providing, however, no details of fatal dose, and referencing only his earlier Honest Herbal (Tyler, 1993). In the earlier work, Tyler states that that overdoses may cause “sweating, rapid heart beat, low blood pressure, and even coma followed by death.” Large doses supposedly may also cause convulsions. The reference cited is a 1977 edition of Martingale: The Extra Pharmacopoeia (Wade, 1997). The 1993 Martingale version states pretty much what Tyler wrote: “symptoms of overdose include profuse diaphoresis, paresis, tachycardia, hypothermia, hypotension and coma; fatalities have occurred (Reynolds).” The assertion in Martingale that deaths have occurred is not supported with any reference, however, and no minimum toxic dose is listed. The 1977 version of Martingale cited by Tyler downplays the supposed dangers of lobelia herb with the following statement: “In large doses lobelia is purgative, emetic, and diuretic, and may cause medullary, vasomotor, and respiratory depression. The symptoms are alarming but rarely dangerous as vomiting usually occurs." Such a statement (“rarely dangerous”) is inconsistent with Tyler’s own conclusion (“the ratio of risk to benefit is very high.”) We will discuss further below the assertion that lack of vomiting with high doses of lobelia presents a threat to health.

Symptoms listed for lobeline sulfate in the 1977 Martingale appear somewhat more serious: “Side effects include nausea and vomiting, coughing, headache, tremors, and dizziness. Symptoms of overdose include profuse diaphoresis, paresis, tachycardia, hypotension, Cheyne-Stokes respiration, and coma. Large doses are convulsant.” Even here, with the concentrated constituent, Martingale in 1977 makes no mention of potential lethal side effects. Assertions of toxicity are again unreferenced, and we don’t know whether the coma or convulsions come from human case reports or from animal toxicology trials, what route of administration may have been involved, or what the lowest toxic dose might be.

The 1977 Martingale cited by Tyler does relate a case study involving one fatality, reviewing a case presented in a letter to the British Medical Journal in 1968 (Wade; McLaren). A 48 year-old woman with bronchitis and asthma was taking orciprenaline sulfate (a sympathetomimetic agent with beta-adrenergic activity) by inhaler, while simultaneously smoking a mixture of lobelia and Datura stramonium. She collapsed shortly after taking two inhalations of the drug and then smoking the herbal mixture for five to ten minutes. Her symptoms were paleness with slight cyanosis, moist skin, dilated pupils, and voiding of the bladder. The fatality cannot be ascribed to lobelia, but would appear from the symptoms to be due to an interaction between they beta-adrenergic drug and datura. Datura contains hyoscyamine and atropine, both strong anticholinergic agents, which would reasonably be contraindicated for simultaneous use with sympathetic stimulants. The role of lobelia, if any, is unclear. The case report also states that the woman had smoked the lobelia-datura preparation alone for 20 years without any adverse effects.

As in Martingale, published statements by DeSmet, Turner and Szczawinski, Lewis and Lewis, and others also leave us at a dead end, leading only to unreferenced assertions similar to those in Martingale and Tyler, and no data on a smallest lethal dose (DeSmet; Lewis and Lewis; Turner and Szczawinski). The U.S. Dispensatory of 1947 (Osol and Farrar), is a similar blind alley, again containing only unreferenced assertions that lobelia may cause “. . . collapse with stupor and coma; in some cases convulsions precede death.” Further readings in the three-page U.S.D. lobelia monograph tell us how to make the N.F. lobelia preparations, but provide no primary references to human toxicity, and offer no least toxic dose. The Dispensatory does report recommendations by conventional physicians in 1938 that 10 mg doses of lobeline hydrochloride by the intramuscular route are a safe and effective respiratory stimulant suitable for use in emergency respiratory collapse, although the Dispensatory authors disagree with the recommendation.

Turning to the U.S. Food and Drug Association, we find a strong assertion of lobelia toxicity. The May 1983 issue of the FDA Consumer contains a list of unsafe plants, including lobelia. The article says: “Overdoses of the plant or extracts of the leaves or fruits produce vomiting, pain, sweating, paralysis, depressed temperatures, rapid but feeble pulse, collapse, coma, death.” The article is unreferenced. The May 1991 issue of the same magazine repeats the claim that lobelia can cause “breathing problems, convulsions, and even coma and death when used in large amounts,” and cites Tyler’s Honest Herbal, described above, as a source. Despite the above assertion in an unofficial publication, the FDA allowed lobeline sulfate to be sold over-the-counter without prescription in doses of 6 mg per day as recently as 1990 as a smoking deterrent (Anonymous, 1990).

The literature of medical doctors of the Eclectic branch of medicine provide more details of lobelia’s alleged toxicity in their early twentieth century literature. Ellingwood states that fatalities have occurred “in a very few cases”, and gives the symptoms in great detail: “Where death has occurred [lobelia’s] influence as a nerve depressant has been plainly shown in the profound, general muscular relaxation, with greatly impaired muscular power, general trembling, shallow respiration, cold, clammy skin, feeble and depressed heart action.” Ellingwood makes no mention of coma or convulsions, and offers no reference, no details of any case, and no smallest toxic dose.

Harvey Felter is more moderate in his statements about fatalities. “Death, when it occurs (in animals) [Ellingwood’s parentheses] is due to respiratory paralysis.” He concludes:

“Lobelia in the ordinary sense of the term, is not a lethal poison. Undoubtedly its injudicious use has and might produce death, but the same is true of many other drugs that are not ordinarily considered as poisons. That the alkaloid lobeline will kill animals has been fully demonstrated. A drop of the alkaloidal solution placed upon the tongue of a strong, healthy, man instantly vomited him. To this property of its alkaloid is undoubtedly due the failure of lobelia to act upon man as a lethal agent. Its emetic action is so prompt and decided that the contained alkaloid does not, under ordinary circumstances, produce fatal results. Given in cases in extremis, the resulting exhaustion from repeated emesis would very likely hasten death, but death would be more likely due to the act of vomiting exhausting the patient than to any poisonous effect of the lobelia (Felter).”

Below, we will discuss Felter’s assertion that emesis reduces the toxicity of lobelia, which implies that lack of emesis may render orally administered doses more dangerous.

Felter provides us with details of two supposed fatalities due to lobelia, both occurring in the early nineteenth century (Felter and Lloyd). In the most famous, Samuel Thomson, founder of the Thomsonian school of medicine, was accused of killing one Ezra Lovett by recklessly administering repeated doses of lobelia (See the accompanying article “The Controversial Death of Ezra Lovett.” Thomson was acquitted of murder charges in that case. Felter also mentions a prosecution against Dr. R.K. Frost of New York City in 1837 for the alleged killing of his patient T.G. French. The patient was apparently put into a “vapor bath” and given “poisonous decoctions of lobelia . . . deleterious herbs which no reasonable man would administer to a dog.” In a ten-day trial, Frost was convicted of fourth degree manslaughter and sentenced to three months in prison (Felter and Lloyd). Felter offers no details of the case, and no record of the dose of lobelia administered. The trial cannot be used as scientific evidence for lobelia toxicity, without information on the nature of the illness treated, other the herbs or conventional methods applied. Felter recommends safe doses of up to 60 grains of the powered leaves of lobelia.

The homeopath Millspaugh condemns lobelia as a lethal poison in very strong terms, even implying that it has been used intentionally by murderers (Millspaugh). He cites as evidence, however, only the case of Ezra Lovett, with his description appearing to have derived entirely from Bigelow’s 1817 Vegetable Materia Medica. Millspaugh cites the court record of the Lovett trial (Mass Reports), also cited by Bigelow, but provides no minimum toxic dose.

Edwin Hale, another late nineteenth century homeopath, likewise condemns lobelia as a poison in his Special Therapeutics. He mentions the case of Ezra Lovett, and also a flurry of alleged lobelia deaths occurring in London during the early 1850s. See the accompanying article “The London Lobelia Trials” for more details. Hale appears to have taken his information about the London deaths from Stille’s earlier Therapeutics and Materia Medica. Although alleging that lobelia can cause coma and convulsions — on the basis of the symptoms reported in the Thomson trial — in Special Therapeutics, Hale fails to mention these in his companion volume Special Symptomology. Likewise, Hale’s colleague homeopath Constantine Hering in his classic ten-volume Guiding Symptoms fails to mention coma or convulsions as possible side effects of lobelia. Hering required at least two credible reports of symptomology before the symptom could be recorded in his work (Hering). Neither of the symptoms appear in contemporary homeopathy books such as Beoricke’s classic Materia Medica or Morrson’s Desktop Guide (Boericke; Morrison).

Stille, of the Regular school, states in 1874 that “a large number of cases have been published” of death from the administration of lobelia, with “some” of these in North America but “a greater number” in London, referring to the alleged deaths in the early 1850’s. Stille names only the case of Ezra Lovett in North America, and provides a primary reference for the deaths in London. According to a story in the London Medical Times and Gazette in May 1854, Dr. Letheby of London testified at a hearing that “thirteen cases of poisoning by lobelia had occurred within the last three to four years, and that in six of these the coroner’s jury had brought a verdict of manslaughter.” Coroner’s juries decide whether charges should be filed, but an actual trial by jury then must be held. According to Stille: “On trial . . . the culprits generally managed to escape until, in 1856, one was convicted and sentenced to three months imprisonment.” As is described in the accompanying article “The London Lobelia Deaths,” a cholera epidemic raged in London during the years in question. At issue in the trials was whether the patients died from herbal treatments or from the natural course of the usually-fatal disease (Griggs). Despite Letheby’s 1854 assertion that thirteen people had died of lobelia poisoning, it seems that coroner’s juries concluded in seven of the cases that the patient had died of the natural course of the disease, and trial juries cleared all but one of the remaining herbalist-practitioners. Despite Stille’s assertion that a “large number of deaths” had occurred, he can name only a single case in North America, in which the practitioner (Thomson) was acquitted, and a single case in London that resulted in conviction. According to both Griggs and Cook, the conviction in London was not for manslaughter, but for practicing as an apothecary (dispensing herbs) without a license.

William Cook, a medical doctor of the physiomedicalist school, published a vigorous rebuttal to allegations of lobelia toxicity in his 1868 Physiomedicalist Dispensatory. He challenges the allegations made in the Thomson trial, and also the conclusions reported concerning the deaths in London (see accompanying articles.) Cook also relates his personal experience administering large doses of lobelia to patients, including infants, the elderly, and patients who failed to expel the dose through emesis. Cook rebuts the assertion that retained doses of lobelia, following lack of emesis, present a danger of toxicity:

“I have myself many times used an ounce of the herb within a few hours, and had it all retained; have given a child of five years four ounces of the seeds inside seven hours, and had it retained; and in doing so have broken up most alarming attacks of disease and promptly restored health from spasmodic conditions that otherwise would have been fatal. Other physicians have done the same, and many of them have given even larger quantities than this. Within the last seventy-five years, it is probable that not less than five thousand active practitioners have used this article every day, in all forms and in all imaginable quantities; and today their united experience comes up with one loud answer to the effect that lobelia is an absolutely harmless [Cook’s italics] agent (Cook). “

Eclectic Physicians Jones and Scudder in 1863 make only the vague assertion of lobelia toxicity: “It acts in a manner similar to tobacco, though it is much milder, and is generally regarded, when given in large doses, as an acro-narcotic poison” (Jones and Scudder, 1963). They proceed to praise lobelia as a therapeutic agent. After describing the unpleasantness of the nauseating properties, sometimes accompanied by anxiety, distress, and perspiration, the authors state: “Nevertheless the usually short duration of these symptoms, and the salutary impressions which it makes upon the system, compensate, in most instances, for any transient deleterious effect which it may produce.” They conclude: “Lobelia is a prompt, safe, and efficient emetic, equaled by few, and surpassed by none, when resorted to for this purpose. . . . As an emetic, it may be resorted to in all cases when a gentle, yet efficient, agent may be demanded.”

Albert Coffin was the foremost Thomsonian practitioner in England, and was responsible for launching the movement there in the late 1830s. He modified the system somewhat in order to use more European herbs, but his followers also used large doses of lobelia imported from the United States. Coffin earned his fame as a lay herbalist, but eventually earned a medical degree. Thus the later editions of his Guide to Health (more than fifty editions were printed between the late 1830s and the 1870s), writing now as an M.D., Coffin comments on the potential toxicity of lobelia:

We have not only administered it in large doses, but have frequently taken it ourselves, and after more than forty years successful use of it, have never found it to produce any debilitating or other injurious effect on the system. We have given the powdered herb in half-ounce doses, one dose each day, for 28 days in succession. This we did in a desperate case of consumption, and the patient not only recovered, but he is now living to testify to the truth of what we have stated.

When administering it, care should be taken to give enough so as to cause it to operate [as an emetic]; more than this will do no harm. (Coffin).

Wood states in 1860 that the alleged toxic dose of lobelia is highly variable: “Nor is the quantity well determined which will ordinarily prove fatal. In fact, the susceptibility to its effects is so variable that no precise statement can be made on this point” (Wood). Wood cites a statement of Letheby of London that 36 grains (about 2.3 grams) is a fatal dose. Wood cannot take this claim too seriously, because he proceeds to recommend doses of 10-30 grains for the treatment of asthma. Eleven years earlier, Wood had failed to present any details of deaths due to lobelia in his monograph in the 1849 edition of the Dispensatory of the United States of America.

Benjamin Colby was a lay herbalist, following the methods of Samuel Thomson, and wrote one of the most popular books on the subject in 1848 (Colby). His Guide to Health is significant in that it reflects the Thomsonian herbalism as it was practiced at its peak of popularity during the 1840s. Colby’s book was also followed as a guide by lay practitioners during the following generation. Colby describes lobelia, and instructs his readers to disregard any consideration for its alleged toxicity (“. . . use a pound of it if necessary to produce the desired result”) (Colby). Colby also quotes the statements of several prominent physicians of the Regular school who spoke out in support of Thomson and lobelia. A Professor Tully, of the Yale Medical school, had studied with Thomson early in his career. Once appointed to the faculty of Yale, he continued to use lobelia and to teach it to his students. In a 1938 letter to a colleague, cited also by Griggs and Cook, Tully states:

“I have now been in the habit of employing this article for twenty-seven years, and of witnessing its employment by others for the same length of time, and in large quantities, and for a long period, without the least trace of any narcotic effect. I have used the very best officinal tincture in the quantity of three fluid ounces in twenty-four hours, and for four and seven days in succession; and I have likewise given three large tablespoonsful of it within half an hour, without the least indication of any narcotic operation. I have superintended experiments with it, made by young men, and always with the same results. . . . I am confident (the old women’s stories in the books to the contrary notwithstanding) that Lobelia inflata is a valuable, a safe, and a sufficiently gentle article of medicine; and I think the time will come when it will be much better appreciated (Colby).

According to Cook, the experiments alluded to by Tully consisted in giving “enormous injections [by enema] of it to dogs, cats, rabbits, and other small animals, none of which could be killed by the article” (Cook).

Colby also cites statements by Dr. Benjamin Waterhouse, the physician of the Regular school who introduced vaccination into practice in North America. Waterhouse taught at Yale University for more than twenty years, but resigned in order to practice using Thomsonian methods (Cook). Waterhouse wrote a letter of introduction for Thomson in 1825 which stated in part: “Dr. Samuel Thomson has the honor of introducing the valuable lobelia to use, and fully proved its efficacy and safety.” The quotation is also reported by Griggs. Colby further quotes Waterhouse: “The efficacy and safety of Lobelia inflata, I have had ample and repeated proofs of, in a number of cases, and on my own person, and have reason to value it equal with any article in our Materia Medica.”

Botanist Constantine Rafinesque describes lobelia and the controversy over it in his 1828 Medical Flora (Rafinesque). He states that by the late 1820’s the herb was “extensively used” but that some members of the medical profession considered it to be a dangerous narcotic, while others disagreed. Rafinesque comes down solidly on the side of toxicity for lobelia, stating: “ . . . in large doses it is a deadly narcotic.” He describes the symptoms of overdose as: “continual vomiting, trembling, cold sweat, and even death.” Rafinesque fails to mention the convulsions and coma that other writers do, fails to describe any actual case of poisoning, and provides no least toxic dose, and provides no reference for his assertion. Rafinesque was not a medical practitioner, and complied the medical sections of his book from the writings and reports of other writers.

Bigelow’s 1817 Vegetable Materia Medica states unequivocally that lobelia is poisonous, citing the court record of the Thomson trial, but naming no other incidences of poisoning than that of Ezra Lovett. Bigelow provides reports of regular physicians who had experimented with lobelia in the preceding eight years (after its introduction into the regular medical literature in 1809 — See below). Ironically, the testimonies he offers from physicians of the Regular school conflict with that given at the trial – the therapeutic doses he recommends as safe overlap with the doses that supposedly killed Ezra Lovett. I will discuss this further below.

The origin in American medical literature of the allegation that lobelia can cause injury or death appears to be James Thacher, in his 1810 American New Dispensatory. Thatcher states: “From some of its effects, says an eminent physician, lobelia seems to be related to the narcotic plants. . . . If the medicine does not puke or evacuate powerfully, it frequently destroys the patient, and sometimes in five or six hours. . . . Even horses and cattle have been supposed to be killed by eating it accidentally.” Other than the horses and cattle mentioned, Thacher cites only the death of Ezra Lovett while under Samuel Thomson’s care as evidence for lobelia’s toxicity. The New Dispensatory appeared the year after the Thomson trial. Thacher’s statement that lobelia can kill a patient within five or six hours is at odds with the allegations in the Thomson trial, where death followed the last administration of lobelia by 24 hours according to the prosecutions account, and by more than 48 hours by Thomson’s account. Regarding the effect of lobelia on grazing animals, Rafinesque describes them 12 years later in his Medical Flora:

When horses and cattle eat it, they are salivated, producing what is commonly called “the Slavers,” which debilitates them, and for which cabbage leaves are said to be a remedy. I was informed that some horses eat it on purpose to medicate themselves; several Euphorbias produce the same effect. (Rafinesque)

A search of modern veterinary and medical literature fails to produce any reports of animal deaths from grazing on lobelia, although an account of the syndrome described by Rafinesque appears for a Mexican species of lobelia (Lopez et al.). Although drawing extensively on Thacher’s earlier work for his own lobelia monograph, Bigelow declines in 1817 to repeat Thacher’s charges that lobelia can kill grazing animals, and the allegation appears to have been a fabrication by Thacher or his unnamed source.

Prior to Thacher’s Dispensatory, the only mention we have of lobelia in the medical literature is an article by Rev. Manessah Cutler in 1809, in which he relates the cure of his own long-standing asthma with a three-tablespoon dose of lobelia tincture. Cutler’s account is reprinted verbatim in Thacher, and paraphrased in Bigelow. Cutler was a prominent physician and medical botanist in Massachusetts. Neither in his 1809 article nor in his testimony for the prosecution in the Thomson trial did Cutler make any mention of possible toxicity of lobelia, which would be surprising if deaths had occurred in Massachusetts prior to that time.

The lobelia monographs of Thacher and Bigelow contain internal inconsistencies that tend to exonerate lobelia as the cause of Lovett’s death. Their most notable contradiction is that the dose range they describe as harmless overlaps substantially with the dose that allegedly killed Lovett. In Thomson’s own writings, as well as in Thacher’s description of Thomson’s treatment of Lovett, Thomson recommends teaspoon doses of the powder, repeated up to three times in a half an hour. According to the prosecution in his trial, Lovett had retained no more than four such doses (Thomson denies that Lovett retained any doses). Both Thacher and Bigelow describe the treatment reported by Dr. Cutler, who took three tablespoons of the tincture within a half an hour, and cured his long-standing asthma. Neither of the two authors nor Cutler make any comment on such a dose being dangerous, even though it is larger than the dose Thomson gave to Lovett. Neither author mentions dangers from cumulative doses over several days, such as had been administered by Thomson. Bigelow instead describes lobelia’s action as rapid, rather than slow-acting and cumulative. Thacher in 1817 recommends doses of 10-20 grains of the powdered leaves, with lower doses repeated frequently if necessary. This dose is approximately a half teaspoon to a teaspoon of the powder, the same recommended by Thomson (Thomson, 1831). Commenting on this inconsistency, Thomson writes: “If a teaspoonful is given by an empiric [herbalist], its effects are fatal, but if the same quantity is administered by a learned doctor, and called grains, it is a useful medicine.” Thacher also suggests: “Of the saturated tincture, 20, 40, or even 60 drops may be given safely to children of one or two years, increasing as occasion may arise.” Bigelow states that by 1817, physicians of Essex County in Massachusetts were routinely administering doses of a teaspoon to a tablespoonful of the tincture. He cites the recommendation of a Dr. Randall that a dram (about a teaspoonful) of the tincture may be repeated at convenient intervals, and further states that Randall had observed no narcotic effects at such doses. Bigelow concludes:

Of the tincture, a teaspoonful given to an adult, will generally produce nausea, and sometimes vomiting. In certain instances, however, much larger doses have been given without producing any other effect than a flow of saliva.

Neither author gives any caution on an upper limit to a safe dose, although, by citing the supposedly fatal doses in the Lovett case, imply that the doses they themselves recommend are equal to, or sometimes higher than, the fatal dose supposedly given to Lovett. One wonders if either gentleman was sincere in their statements that the doses given to Ezra Lovett could have produced his death.

Thacher’s unreferenced and unsupported assertion that if lobelia does not produce vomiting it can produce toxicity does not stand the test of subsequent historical accounts, or even of twentieth century standard medical practice. The accompanying table shows some historical doses of lobelia, including accounts of large doses retained without emesis. Furthermore, lobelia was often administered by enema specifically to retain the dose. Such use is mentioned as a childbirth aid (to relax the pelvic muscles) in both Colby in 1848 and Ellingwood in 1919, as well as other authors in between (Cook; Felter and Lloyd) Physician Eli Jones also mentions a case in which he administered a large amount of lobelia tincture by enema in the case of a bowel obstruction:

I prepared an injection of saturated lobelia tincture, four ounces in three quarts of warm water. With a syringe with a long tube, I injected some of the liquid as far up her bowels as I could get it. . . . The injection produced a relaxation of the obstruction in the bowels; she started to vomit and said she felt something “give way” in her bowels. It was the intestine slipping back in its normal position after invagination. I left her out of danger, and she eventually recovered (Jones).

Jones apparently had no fear that the dose would be retained, and reports that he took precautions to make sure that the dose was retained and not evacuated. As recently as the 1970’s standard pharmacology texts in the U.S. recommended doses of up to 20 milligrams of lobeline hydrochloride as an emergency respiratory stimulant, administered by intramuscular injection, and thus 100% retained (Gisvold and Doerge). The equivalent amount of lobeline would be found in about 5 grams of powdered leaf, or a greater amount of alkaloid than supposedly killed Ezra Lovett. Lovett allegedly died of respiratory collapse, but here we have a similar dose of the alkaloid, one probably much better absorbed through the intramuscular route than the oral route used by Thomson, used to treat respiratory collapse.

Thacher’s and Bigelow’s shaky and inconsistent evidence seems to be the sole basis for the subsequent listings of lobelia toxicity in American medical literature. Says Cook:

From that date [1817, referring to Thacher’s later edition] to the present [1868], it is probable that every Allopathic Materia medica that mentions lobelia contains the assertion that Thomson was tried for committing murder by the use of it. Griffith, Pereira, Christison, the United States Dispensatory, Royle, Dunglison, Taylor, and Carson are among the standard authors who use the nearly stereotyped phrase, “Thomson himself was tried for murder for killing a man with this article” (Cook).

According to Cook, no death from lobelia had entered the medical literature between the time of the Thomson trial (1809) and the time of Cook’s writing (1868). Claims of lobelia’s potentially fatal toxicity must then sink or swim on the strength of the references in Thacher and Bigelow, and on the merits of the charges in the Thomson trial, because all listings thereafter, including toxic symptoms of coma, convulsions, respiratory collapse, and death, appear to be derived from these authors, and through them, from the symptoms accompanying the death of Ezra Lovett. For an exhaustive exposition of the details of the Thomson trial and of Lovett’s illness, treatment, and death, see the accompanying article “The Controversial Death of Ezra Lovett.” It appears from the facts in that article that Lovett died of the natural course of meningitis, or possibly from louse-borne typhus, both of which have neurological symptoms prominent, and both of which are often fatal.

Finally, we come to the allegation that lobelia is cathartic. The alleged motive for Thomson to administer the final “deadly dose” of lobelia to Lovett was to produce catharsis through the bowels (Atkins). Cutler also asserted the year of the trial that lobelia has a cathartic effect. Thomson denies in his own writing that lobelia is cathartic, and denies that he had any such intention in treating Lovett (Thomson, 1831). Rafinesque refers to the assertion of a cathartic effect for lobelia as an outdated misconception by 1829 (Rafinesque). Of the authors above who used lobelia regularly in their practice, none reports a cathartic effect. Reports of this alleged property of lobelia survive today in Martingale (Reynolds).


In conclusion, no credible evidence of lobelia toxicity or any adverse effect more serious than vomiting is present in the medical literature of the past two centuries. Twentieth century literature that alleges lobelia toxicity provides no primary references or alleged least toxic dose. Modern allegations appear to be parroted uncritically from early nineteenth century sources. Nineteenth century literature presents only two cases of successful legal prosecution of herbalists in connection with deaths alleged to be due to lobelia. On the other hand, another case in North America and at least twelve court cases in England resulted in acquittal of the herbalist. Only a single case occurs in the literature – that of Ezra Lovett in 1808 – where details of alleged dose and supposed toxic symptoms appear. The practitioner (Samuel Thomson) was acquitted in that case, and, when given an opportunity in a later court case, presented witnesses rebutting the prosecution testimony in the trial. Much larger doses than the one alleged to have killed Thomson were subsequently used in medical practice with no ill-effects. The nineteenth-century literature is divided between medical practitioners who used lobelia regularly and in large doses, and those who used is hardly at all. The unanimous consensus of those who actually used it in practice is that it is a harmless agent without potential for toxicity beyond its nauseating effects. Supporting this view is the twentieth century use of lobelia hydrochloride in large intramuscular, subcutaneous, and intravenous doses through the 1970s, and the non-prescription use of oral doses of lobeline sulfate as recently as 1990.


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Copyright 2001 Paul Bergner  

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