Although the highly toxic nature of castor bean (Ricinus communis) is well recognized, reports of human toxicity in the English medical literature are scarce. The potentially lethal doses reported for children and adults are three beans and four to eight beans respectively. Recent experience with two cases provides added insight into the expected course of toxicity. In both cases, repeated vomiting, diarrhea, and transiently elevated serum creatinine occurred. Dehydration was much more pronounced in the second case. Both patients recovered uneventfully. Other reported manifestations of castor bean toxicity, such as hepatic necrosis, renal failure, erythrocyte hemolysis, convulsions, and shock, did not occur.