Merck Manual

Please confirm that you are a health care professional

honeypot link

Plant Poisoning


Gerald F. O’Malley

, DO, Grand Strand Regional Medical Center;

Rika O’Malley

, MD, Albert Einstein Medical Center

Last full review/revision Apr 2020| Content last modified Apr 2020
Click here for Patient Education
Topic Resources

Highly toxic and potentially fatal plants include the following:

  • Castor beans and jequirity beans

  • Oleander and foxglove

  • Hemlock

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 delirium, seizures, coma, and death. Whole-bowel irrigation Whole-bowel irrigation Poisoning is contact with a substance that results in toxicity. Symptoms vary, but certain common syndromes may suggest particular classes of poisons. Diagnosis is primarily clinical, but for... read more should be considered because it aims to remove all beans ingested.

Oleander and foxglove


Hemlock poisoning (poison hemlock and water hemlock) can cause symptoms within 15 minutes.

Poison hemlock has nicotinic effects, beginning with dry mouth and progressing to tachycardia, tremors, diaphoresis, mydriasis, seizures, and muscle paresis. Rhabdomyolysis Rhabdomyolysis Rhabdomyolysis is a clinical syndrome involving the breakdown of skeletal muscle tissue. Symptoms and signs include muscle weakness, myalgias, and reddish-brown urine, although this triad is... read more and bradycardia may occur.

Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Test your knowledge

More than 60,000 bites and stings are reported to poison centers in the US each year, about 45,000 of which are snakebites (of which 7,000 to 8,000 are venomous and cause about 5 deaths). Which of the following types of snakes accounts for the majority of these bites and almost all deaths? 
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest