A few commonly grown plants are highly poisonous, and many plants are moderately poisonous (see table Moderately Poisonous Plants) (1, 2). Few plant poisonings have specific antidotes. Most plant ingestions, including the plants listed in the aforementioned table, result in minimal symptoms unless the leaves and other components are concentrated into a paste or brewed into a tea.
Highly toxic and potentially fatal plants include the following:
Castor beans and jequirity beans
Oleander and foxglove
Hemlock
(See also General Principles of Poisoning.)
Castor beans and jequirity beans
Castor beans contain ricin, an extremely concentrated cellular poison. Jequirity beans contain abrin, a related and even more potent toxin. In both, the beans have a relatively impervious shell; thus, the bean must be chewed to release the toxin. However, the seed coating of the jequirity bean is often not intact, and simple bacterial digestion can release the abrin toxin.
Symptoms of either poisoning may include delayed gastroenteritis, sometimes severe and hemorrhagic, followed by multiorgan failure including renal failure and cardiovascular collapse. Whole-bowel irrigation should be considered because it aims to remove all beans ingested (3, 4, 5).
Oleander and foxglove
These plants and lily of the valley (which is similar but less toxic) contain digitalis glycosides. Foxglove was the original source of the medication digitalis. Toxicity includes gastroenteritis, confusion, hyperkalemia, and arrhythmias. The serum digoxin level can confirm ingestion but is not useful as quantitative information.These plants and lily of the valley (which is similar but less toxic) contain digitalis glycosides. Foxglove was the original source of the medication digitalis. Toxicity includes gastroenteritis, confusion, hyperkalemia, and arrhythmias. The serum digoxin level can confirm ingestion but is not useful as quantitative information.
Potassium levels are closely monitored. Hyperkalemia may respond only to hemodialysis. Use of calcium as part of the treatment of arrhythmias due to digitalis glycoside poisoning is controversial (6). Digoxin-specific fractionated antibody (Fab) fragments have been used to treat ventricular arrhythmias.). Digoxin-specific fractionated antibody (Fab) fragments have been used to treat ventricular arrhythmias.
Hemlock
Hemlock poisoning (poison hemlock and water hemlock) can cause symptoms within 15 minutes.
Poison hemlock has effects on the nicotinic cholinergic receptor, beginning with dry mouth and progressing to tachycardia, salivation, tremors, diaphoresis, mydriasis, and seizures. In severe cases, bradycardia, coma, and ascending paralysis that leads to respiratory failure may occur. Rhabdomyolysis may also occur.
Water hemlock seems to enhance gamma-aminobutyric acid (GABA) activity. Symptoms may include gastroenteritis, delirium, refractory seizures, and coma.
Moderately Poisonous Plants
Plant | Symptoms | Treatment |
|---|---|---|
Aconitine (eg, derived from monkshood) | Bradycardia, arrhythmias, paresthesia, weakness | Supportive care Sodium bicarbonateSodium bicarbonate |
Aloe spp | Gastroenteritis, nephritis, skin irritation | Supportive care and skin irrigation with soap and water |
Aristolochia spp (birthworts, pipevines) | Supportive care | |
Azalea | Cholinergic symptoms | Supportive care and atropineSupportive care and atropine |
Caladium spp (elephant ear, angel's wings) | Oral mucosal damage due to calcium oxalate crystals in leaves | Supportive care and demulsification (eg, with milk or ice cream) |
Capsicum spp (peppers) | Mucous membrane irritation and swelling | Supportive care, irrigation |
Colchicine (autumn crocus, meadow saffron, glory lily)Colchicine (autumn crocus, meadow saffron, glory lily) | Delayed gastroenteritis, multiple organ failure Bone marrow suppression | Supportive care and possibly, as a last resort, experimental colchicine-specific Fab fragments*Supportive care and possibly, as a last resort, experimental colchicine-specific Fab fragments* |
Cyanogenic glycosides (eg, in Prunus spp [eg, peach, apricot, and wild cherry pits], Malus spp [eg, apple seeds], and other seeds) | Symptoms of cyanide poisoning | HydroxocobalaminHydroxocobalamin Cyanide antidote kit (includes amyl nitrate, sodium nitrite, and sodium thiosulfate)Cyanide antidote kit (includes amyl nitrate, sodium nitrite, and sodium thiosulfate) |
Deadly nightshade | Anticholinergic symptoms, hyperthermia, seizures, hallucinations | Supportive care For severe hyperthermia or seizures, possibly physostigmineFor severe hyperthermia or seizures, possibly physostigmine |
Dieffenbachia (dumbcane) | Oral mucosal damage due to calcium oxalate crystals in leaves | Supportive care and demulsification (eg, with milk or ice cream) |
Fava beans | In patients with G6PD deficiency, gastroenteritis, fever, headache, hemolytic anemia | Supportive care For severe anemia and poisoning, consideration of exchange transfusion |
Green potato and potato sprout | Gastroenteritis, hallucinations, delirium | Supportive care |
Holly berries | Supportive care | |
Jimsonweed | Anticholinergic symptoms, hyperthermia, seizures, hallucinations | Supportive care For severe hyperthermia or seizures, possibly physostigmineFor severe hyperthermia or seizures, possibly physostigmine |
Licorice (not the artificially flavored licorice candy) | Hypokalemia, hypertension, and retention of water and sodium (pseudohyperaldosteronism) | Supportive |
Lily of the valley | Hyperkalemia, gastroenteritis, confusion, arrhythmias | |
Mistletoe | Supportive care | |
Nettle | Local stinging and burning | Supportive care |
Nightshade, common or woody | Gastroenteritis, hallucinations, delirium | Supportive care |
Pennyroyal | Hepatotoxicity | N-acetylcysteine |
Philodendron spp | Oral mucosal damage due to calcium oxalate crystals in leaves | Supportive care and demulsification (eg, with milk or ice cream) |
Poinsettia | Minor mucous membrane irritation | Unnecessary |
Poison ivy | Dermatitis | See Dermatitis |
Pokeweed | Mucous membrane irritation, gastroenteritis | Supportive care |
Pothos | Oral mucosal damage due to calcium oxalate crystals in leaves | Supportive care and demulsification (eg, with milk or ice cream) |
Yew | Rarely, seizures, arrhythmias, coma | Supportive care |
* Available only in France. | ||
Fab = fractionated antibodies; sp/spp = species. | ||
References
1. Krenzelok EP, Mrvos R. Friends and foes in the plant world: a profile of plant ingestions and fatalities. Clin Toxicol (Phila). 2011;49(3):142-149. doi:10.3109/15563650.2011.568945
2. Froberg B, Ibrahim D, Furbee RB. Plant poisoning. Emerg Med Clin North Am. 2007;25(2):375-ix. doi:10.1016/j.emc.2007.02.013
3. Rasetti-Escargueil C, Avril A. Medical Countermeasures against Ricin Intoxication. Toxins (Basel). 2023;15(2):100. Published 2023 Jan 20. doi:10.3390/toxins15020100
4. Centers for Disease Control and Prevention. The National Institute for Occupational Safety and Health (NIOSH). Abrin: Biotoxin. Accessed January 30, 2025.
5. Centers for Disease Control and Prevention. The National Institute for Occupational Safety and Health (NIOSH). Ricin: Biotoxin. Accessed January 30, 2025.
6. Levine M, Nikkanen H, Pallin DJ. The effects of intravenous calcium in patients with digoxin toxicity. J Emerg Med. 2011;40(1):41-46. doi:10.1016/j.jemermed.2008.09.027
