AbstractThe effects of three dosage levels (250 mg/kg, 600 mg/kg, 800 mg/kg per os) ofCroton penduliflorusseed oil were studied in mice. The mice were dosed with the oil suspension in 5% Tween 20 through oral intubation. Five mice from each dosage group were slaughtered at 3 h, 9 h and 24 h post‐treatment with the oil. Various segments of the gastro‐intestinal tract and visceral organs including the liver, lung, kidney, spleen, testis, adrenal glands and heart were examined grossly and tissue sections were collected for histopathological examination. Croton oil initiated hypersecretions in all segments of the gastro‐intestinal tract. It also produced oedema in the stomach and mild inflammatory reactions in the jejunum, ileum and colon. The liver, lung and myocardium were the most affected of the visceral organs when mice were dosed with high levels (600 mg/kg and 800 mg/kg) of croto