Castor Bean Leaf Toxicity


The castor bean plant produces ricin, a deadly poison that has been used in assassinations and is so deadly that both sides in World War I, despite possessing the poison, avoided its use as a chemical weapon. However, the castor bean plant is also deceptively beautiful, tropical in appearance with colorful flowers and patterned seeds that, despite their deadliness, have been used to create jewelry and rosaries.


Castor bean plants contain ricin, one of the world's deadliest poisons. Within a few hours of ingesting ricin, people experience abdominal cramps, vomiting and diarrhea, sometimes containing blood. This causes severe dehydration and decreases in urine volumes, followed by drops in blood pressure. Death occurs within three to five days, and if a person survives beyond that time frame, it is unlikely that the poisoning will be fatal.


Although the most toxic part of the castor bean plant is its seeds, the poison occurs in the plant's sap, making the whole plant poisonous, including the leaves. Ricin is so concentrated in the seeds that one milligram can kill an adult. Concentrations are lower in the leaves, making them less deadly.


The castor bean plant grows rapidly, reaching heights of six to 15 feet in a single season, and may grow to resemble a small tree in climates where it does not die back during the winter. Its leaves are distinctive, broad and palmate, meaning that the lobes spread like fingers from the palm of your hand. The leaves may reach 20 inches in width. Castor bean plants produce red, star-shaped flowers and spiky seed pods, each of which contains a single intricately mottled seed.


Castor bean plants are particularly dangerous to children, who are often attracted to the plant by the attractive seeds. Because children are more sensitive to fluid loss and become dehydrated quickly, ingestion of the leaves--even though less toxic than the seeds--poses a significant risk. The Cornell University Department of Animal Science recommends that castor bean plants not be kept in the house with small children. In areas where castor bean plants grow in the wild, teach children to identify the plants and avoid them, especially the seeds.


Aphids that feed on a castor bean leaf will die of ricin poisoning. Consuming castor bean leaves that grow in pastureland poses a risk to livestock and other animals, with horses the most susceptible. Affected animals exhibit similar signs of poisoning as humans, in addition to convulsions, paralysis, heart contractions and muscle tremors. Poisoned animals show an elevated body temperature, weak pulse, cold extremities and disruptions in eating and digestion.

Keywords: castor bean poisoning, castor leaf poisoning, castor leaf dangers

About this Author

First published in 2000, Dawn Walls-Thumma has served as an editor for Bartleby and Antithesis Common literary magazines. Her work has been published academically and in creative journals. Walls-Thumma writes about education, gardening, and sustainable living. She holds a Bachelor of Arts in psychology and writing from University of Maryland, and is a graduate student in education at American Public University.