Castor Seed Poisoning in Humans: A Review

This work reviews 314 cases of poisoning, including 15 deaths which occurred in humans as a result of castor seed ingestion between 1738 and 1988. Castor seed toxicity is due to ricin, a powerful phytotoxin present in the plant and concentrated in the seeds. Ingestion of castor seeds is extremely dangerous. In some parts of the world it is customary to eat one seed for purgative purposes. However, if they are well chewed, 2 or 3 seeds may be fatal to a child and 8 seeds to an adult. There is a latent period of 3 to 20 hours before the signs of toxicity appear. Manifestations of toxicity include internal hemorrhage and gastrointestinal irritation, nausea, violent vomiting, abdominal pain, severe diarrhea, dilation of the pupils, and shivering. Convulsions occur in severe poisoning. The clinical features of poisoning give no clue to the diagnosis. The mode of action of ricin is not well understood, and at the present time no antidote for castor seed poisoning is available. Hospital treatment for the poisoned patient is entirely supportive. Following seed ingestion gastric lavage is employed to remove any remaining seeds from the stomach, followed by an appropriate dose of activated charcoal to bind the released ricin. Fluid and electrolyte balance must be maintained. In most cases the patient remains hospitalized for 3 to 14 days. Keywords: Ricin, Caster beans, Poisoning, Humans, Symptoms, Treatment.