OBJECTIVE Gongronema latifolium leaves have been used in folklore medicine to manage diabetes mellitus and alleviate dyspepsia. This study aimed to provide a pharmacological basis to the medicinal use ofGongronema latifolium as an antidiabetic and antiulcerogenic agent in diabetes mellitus. METHODS Ethanol extract from the leaf (200 mg/kg bodyweight) of Gongronema latifolium was administered to both streptozotocin-induced diabetic and control groups orally for 14 days. Gastric acid secretion was measured and ulcer was induced using ethanol and four-hour pyloric ligation. RESULTS The mean bodyweight was significantly lower (p < 0.01), while the mean weight of the stomach, liver and small intestine to bodyweight ratio was increased significantly (p < 0.05) in the two diabetic groups compared to control. Extract significantly (p < 0.01) reduced the blood glucose level similar to the non-diabetic control. Basal and stimulated acid secretion in diabetic control rats was significantly (p < 0.01) decreased when compared to control. Extract administration increased the stimulated gastric acid secretion to a level significantly (p < 0.05) higher than control while reduction in gastric secretion by ranitidine was similar compared with control. Gongronema latifolium treatment significantly (p < 0.05) reduced ulcer scores in both ulcer models and increased mucus weight in the diabetic group. CONCLUSIONS These results suggest that Gongronema latifolium antiulcerative activity is due to its prevention of chemical-induced stomach injury.