Muell. Arg. is often used in traditional medicine by Ibibios of Niger Delta region of Nigeria for the treatment of several diseases including gastrointestinal disorders especially ulcer. The antiulcer activity of the ethanolic extract of the crude leaf extract was investigated against indomethacin, ethanol and histamine – induced ulcer models in rats. The crude leaf extract of Croton zambesicus
(200 – 600mg/kg) significantly (p<0.001) inhibited ulcers produced by the ulcerogens used; indomethacin, ethanol and histamine.The results of this work suggest that the leaf extract of Croton zambesicus
possesses antiulcer activity, supporting the ethnomedical use of the plant.