The Herbarium at the University of Georgia Poisonous Plants of Georgia
The Herbarium of the University of Georgia, Athens, Georgia
Common Name:
Scientific Name:
Castor bean Ricinus communis L.
Family:
 Euphorbiaceae
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This plant may be poisonous to both humans and animals. Please refer to the "Symptoms" section below for information regarding susceptiblity of animal species to poisoning.
Description:
 Castor bean is an annual or perennial herb with alternate shield-shaped leaves that are palmately lobed. Each leaf has 7-9 serrated lobes. The leaves are up to 16 in long and the leaf stalks may be 12 in long. The flowers form a compact cylindrical cluster. The flowers lack petals but appear white. The fruits are red and spiny. The seeds are gray to brown, mottled, shiny and about ½ in long. This plant has an attractive maroon color and is popular as an ornamental.
Toxic Part: The seeds are toxic.
Toxin: Ricin, a glycoprotein (lectin) is found in highest concentration in the seeds. When ingested orally, ricin passes through the digestive tract intact or it is degraded to peptides. However, if ricin is injected as was the case in the assassination of a Bulgarian broadcaster, a dose as little at 2 millionths of body weight can prove fatal.
Symptoms: When castor beans are consumed by people common symptoms include throat and mouth irritation, vomiting, and diarrhea although the toxicity of the seeds has been disputed. Although the information on castor bean poisoning is confusing, most of it indicates that ingestion of the seeds can cause symptoms of poisoning. Many people have experienced significant illness associated with seed consumption. It should be noted that all animals are susceptible to castor bean poisoning.
Treatment: There is no antidote for ricin. Treatment for castor bean ingestion involves induced emesis with activated charcoal and administration of fluids.
References: 24, 30, 96, 104, 105, 129, 152
This site is NOT a substitute for the advice of medical physician. Plant poisonings can, in certain cases, result in SERIOUS HARM AND EVEN DEATH. Please contact a physician or your local poison control center if you suspect any plant poisoning. A link to the Georgia Poison Control Center can be found on the "References and Links" page of this site.