Food Poisoning by Oleander Skewers: Investigation of a Toxicologic Urban Legend

Background

Urban legends are a form of modern folklore in which unusual, humorous, or lurid stories are told as true, but which are likely untrue or distortions and exaggerations of the truth. Urban legends typically combine second-hand narratives, combined with contemporary settings and familiar everyday objects. Urban legends influence people’s thoughts and feelings on various topics, despite largely originating without the support of facts or concrete evidence. According to professor of folklore Jan Harold Brunvand, urban legends are “realistic stories concerning recent events (or alleged events) with an ironic or supernatural twist.” They also have a “strong basic story appeal, a foundation in actual belief, and a meaningful message or ‘moral’” with the mark of success indicated by the number of people who have heard or showed interest in such tales [1].

Poisoning through casual contact with oleander (Nerium oleander) plants appears to be one example of an urban legend. Oleander plants are commonly used in landscaping in warmer climates, especially along highways where their hardiness and drought resistance are necessary for continued survival. However, multiple reports of oleander toxicity have been noted in medical literature [2, 3]. Although the most serious cases are caused by ingestions with suicidal intent, it is a commonly held belief that more casual contact with oleander plants may cause significant toxicity [2]. For instance, it has been suggested that one may become unintentionally poisoned by sleeping near oleander plants, drinking water into which oleander flowers have fallen, or inhaling the smoke produced by burning oleander plants [3–5]. But perhaps the most prevalent of these claims is the belief that one may become poisoned by eating food cooked on oleander branch skewers [3]. This latter mechanism is seen as part of a cautionary story about some unfortunate Boy Scouts who died, or became very ill, as a result of cooking hot dogs using oleander skewers [6]. Such claims have been repeated many times in both the medical and the lay literature; yet, there remains a paucity of documented cases of oleander toxicity via unintentional mechanisms [2–5]. Therefore, we hypothesize that perhaps no cases of oleander toxicity through casual contact, and specifically through the use of oleander in food preparation, have been satisfactorily documented, and that all such claims may have manifested from a widely-held, popular urban legend.

Methods

A PubMed search was conducted using the keywords “oleander” and “oleandrin.” All results were reviewed to find case reports/series involving human exposures. The relevant articles were reviewed for any description of poisoning through the use of oleander in food preparation. A “Google” search was similarly conducted using multiple variations of the keywords “oleander,” “Nerium,” “hot dog,” “skewer,” “food,” “poison,” and “poisoning” for other reports or descriptions of these incidents. The reference sections of all articles obtained above, the relevant chapters from several medical toxicology textbooks, and one of the author’s (JRS) personal collection of literature regarding oleander were recursively searched to find the original source(s) of these reports. In this recursive search, no limitation was made to the primarily medical (vs. botanical, historical, or other) literature, language, or to the year of publication. Several of the references identified were published in French; translation to English was performed with Google Translate. When these publications are quoted, the direct English translation is provided.

Results and Discussion

The origin of reports relating to oleander toxicity by use of oleander skewers in cooking is consistent in implicating some herald events occurring in military history. Although some sources suggest an origin in association with Alexander the Great (fourth century BCE) or during the Crimean War (1854–1856), the majority of the reports agree that a mass-casualty event involving oleander poisoning occurred during the Napoleonic wars of the early nineteenth century [7, 8]. Other reports agree that the event took place among French troops in Spain, although the exact location of the event and the number of persons affected varies [9–12]. A few reports published in the French scientific literature in the mid-nineteenth century (decades after the Napoleonic wars) give some details of this event, although no reports contemporaneous with the alleged event could be found [9–12]. Whether this index event of mass poisoning actually occurred as recorded or has been elaborated upon in the retelling is not clear.

Additional reports in mid-nineteenth century French medical literature provide descriptions of some early occurrences of alleged oleander skewer toxicity. An 1843 report regarding plant poisonings with Conium maculatum (poison hemlock) and with oleander states that the index mass-casualty event occurred in 1809 near Madrid. While foraging for supplies, one French soldier was said to have used branches of oleander as skewers to roast meat. Twelve soldiers who ate this meat became dangerously ill and five of them died, although no other clinical details are given. The following day, a ban against using oleander for skewering food was made by the military authorities [13].

In this 1843 publication, Julien Larue du Berry, a French military pharmacist-surgeon, reported a similar event that had occurred 2 years earlier among troops stationed in northern Africa. One soldier used an oleander stick to stir a pot of barley he was cooking, and five men who ate this meal became ill. Each soldier’s symptoms were individually described (quotes are Google translations of the original document). The first solider was “strongly agitated and made acute cries; his eyes were projecting, and his pupils excessively dilated; he vomited a liquid matter, slightly greenish.” The second soldier “had dilated pupils, light convulsive contractions of the limbs, and gave plaintive cries. Not vomiting.” A third soldier was “vertiginous, complained about pains to the stomach and the joints of the leg: he was stupefied, and did not understand what one said to him. He was the least sick.” The fourth “had his head leaning on the chest, and was in a state of complete insensibility.” The fifth had “haggard eyes; he appeared completely astounded; from time to time he made movements with the head; he vomited a matter charged with bile.” They were all treated with hot water containing emetic, rectal injections of oil, bleedings, and herbal tea. All five were able to return to duty within 8 days [13].

The author of this case series also mentions the earlier writings of Libantius, a Venetian scientist (circa fourth century CE), who had reported an individual poisoned through use of an oleander branch skewer to cook a roast, with the resultant symptoms of agitation, insanity, syncope, and death [13]. Libantius reportedly also wrote that one may become poisoned by sleeping in a room containing oleander flowers. Larue, however, dismissed this latter claim, since he and many other French officers had slept on makeshift mattresses constructed of oleander branches without any ill effect [13]. Libantius was also referenced in the homeopathic literature of the late nineteenth century, where he is said to have reported the death of a girl who locked herself in a room full of oleander flowers. Libantius also described another girl who had feelings of “restlessness, swoons, and insanity” before her eventual death after she had eaten a roast that was cooked on a branch of oleander wood [14]. Thus, commonly-held beliefs in the nineteenth century about oleander may have originated from the teachings of an ancient scholar whose primary documentation could not be located in our literature search. Furthermore, the symptoms described in Larue’s case series, even including his secondary report of Libantius’ ancient case, appear more consistent with an anticholinergic toxidrome than with the currently understood effects of oleander toxicity. The reported mydriasis, agitation, altered mental status (stupefication), convulsive activity of the limbs (possibly myoclonus), and return to baseline over several days are all consistent with the effects of the antimuscarinic compounds found in several poisonous plants, such as Atropa belladonna, and in Hyoscyamus, Brugmansia, and Datura species.

An 1857 report details some early efforts to chemically describe the toxic components of oleander. The author also makes brief reference to the mass poisoning of an army corps commanded by Marshal Louis-Gabriel Suchet, duc d’Albuféra, in which there were many losses (“pertes nombreuses”) following a meal in which meat had been cooked and skewered with branches of oleander. No clinical details of the event are given. This event is presumably the same one mentioned above as occurring in the vicinity of Madrid in 1809, although the approximate location and date of the event are not specified in this report [10].

Another 1857 report, discussing a poisoning by Taxus baccata (English yew), also makes reference to a mass poisoning of soldiers during the Spanish campaign. This author states that a brigade of Suchet’s army corps had been deprived of food for several days and then suddenly acquired a great quantity of meat. The soldiers used oleander branches to skewer the meat, as this plant grows well in the valleys of Catalonia. More than three hundred soldiers are reported to have become ill, and an undisclosed number of them succumbed to the poisoning [12].

In light of these French nineteenth century reports, it is notable that Marshal Suchet himself made no mention of any mass poisoning among his troops, from oleander or otherwise, in his memoirs published in 1829, only 14 years after the war’s end [15]. One might expect such an unusual event to merit inclusion in the 932-page memoirs of a military man admired, according to the author of the memoir’s preface, for recording “every circumstance deserving of notice” (pg. ix), including “the names of many officers, and the particulars of many trifling engagements.” (pg. xii) [15]. Admittedly, these memoirs focus primarily on larger battles and troop movements involving many hundreds or thousands of men. Yet, Suchet often also recounts many smaller events involving a few dozen men, and in some instances as few as only four soldiers or a single officer in a particularly gallant action. Suchet was well-respected, since “his first care was to procure [his soldiers] the means of sustenance…and to provide for their wants.” Suchet recounts the difficulties encountered in keeping his men supplied with provisions and twice specifically details the acquisition and disposition of meat to his troops (pp. 328–9, vol. 1; and pg. 12, vol. 2) [15]. Neither of these instances occurred near Madrid or in 1809, and no adverse effects related to poisoning are described.

Poisoning through food cooked on oleander skewers has been alluded to several times in the recent medical and scientific literature [16–18]. However, rather than giving any details of an actual poisoning, these reports merely make statements assuming such a mechanism has previously been established as fact. When any supporting references are given, they are secondary references from the botanical literature, rather than primary case reports or studies. A 1995 publication states that “persons using oleander sticks to cook hot dogs were poisoned” in Florida, but gives no clinical details, no dates or locations of the incidents, or primary references. All listed references specifically relating to Florida are secondary botanical references [16]. In a 1999 case report of a suicidal ingestion of oleander, it is stated that poisoning has occurred by “making campfires, mixing soups, [and] skewering hot dogs” with oleander branches, but no supporting reference is provided [17]. In a 2000 review article in Fire Technology, Nelson states that “[p]eople have been fatally poisoned by eating meat cooked on skewers of oleander” [18]. Three potential references are listed, yet all of these are secondary references from the botanical literature and do not provide any details of people poisoned through the oleander skewer mechanism [19–21].

The above references stand in contrast to a 1996 review article regarding oleander toxicity appearing in Toxicology. Langford and Boor reviewed over 200 cases of human oleander poisoning (either Nerium oleander, or Thevetia peruviana [yellow oleander]) from the medical literature between 1979 and 1992. The majority of these cases resulted from intentional ingestion of Thevetia peruviana (now called Cascabela thevetia due to taxonomic changes), a common suicide method in southern Asia. Although the authors specifically mention the possibility of oleander poisoning via “inhalation of smoke or the ingestion of sap or honey produced from oleanders,” for which they provided no specific references, they nowhere mention any case resulting from using oleander branches to skewer and cook food. All of the human poisoning cases they reviewed occurred due to intentional ingestion of plant parts, most commonly the leaves, leaf extracts, or seeds [5]. In 2021, Suchard and Greb reported an investigation of the potential for oleander toxicity via a food skewer mechanism, by measuring the oleandrin content of hot dogs cooked on both dried and fresh oleander skewers. This study found that hot dogs cooked on oleander skewers contained a negligible amount of oleandrin, a few orders of magnitude less than that needed to cause human poisoning [22].

Conclusion

Oleander poisoning through casual contact, without the intention for self-harm, has been reported in both medical and non-medical sources for centuries. Unsurprisingly, the earliest reports contain no scientific analyses that might confirm exposure, let alone poisoning, and even the clinical descriptions provided do not appear particularly consistent with cardioactive steroid poisoning. The earlier reports appear to have been interpreted and repeated as fact up through modern times. Within the last several decades, when convincing evidence of toxicity would be possible, no identifiable cases of oleander poisoning through casual contact have been reported. In this latest time period, multiple well-documented cases of oleander toxicity through intentional exposure to cause self-harm continue. Yet, claims that poisoning through the use of oleander branches as food skewers can occur, or indeed has occurred, continue in medical and popular culture publications.

This situation is consistent with the definition provided by Professor Brunvand regarding what constitutes an urban legend [1]. The concept of a person inadvertently poisoning or killing themselves in the seemingly wholesome process of self-sustenance around a campfire holds a morbid appeal. There is enough scientific fact to make the story appear feasible, as long as it not subjected to strict evidentiary standards. This story is repeated as a realistic second-hand narrative, combining everyday objects (branches, hot dogs, campfires, and Boy Scouts) with an ironic twist (a meal resulting in poisoning or death, instead of satisfying hunger) and a potential moral: to be wary of unexpected poisons in nature.

Declarations

Conflict of Interest

None.

Sources of Funding.

None.