The ethanol extract (EE) of the aerial parts of Solanum variabile Mart. (Solanaceae) was investigated for its ability to prevent ulceration of the gastric and duodenal mucosa at different doses. Its ability to heal chronic ulcer processes was also evaluated. When the HCl/ethanol solution was used to induce gastric ulcer, the EE produced a significant dose-dependent reduction of lesion formation of 51, 74 and 89%, at doses of 250, 500 and 1000 mg/kg, respectively. The 100 mg/kg dose had no significant activity. The EE also significantly reduced the gastric lesions induced by the combination of indomethacin and bethanechol (60 and 72%) at doses of 500 and 1000 mg/kg and also reduced stress-induced gastric ulcer (41%) but only at the doses of 1000 mg/g (P < 0.05). The pylorus-ligature experiment demonstrated that the highest EE dose affected significantly the gastric juice parameters by increasing pH values from 4.08 (negative control) to 5.42 and decreasing acid output from 7.16 (negative control) to 4.26 mEq.mL, 4h. A decrease of gastric contents from 370 mg (negative control) to 240 mg was also observed. The results obtained in the chronic gastric ulcer model indicated that a single oral dose of Solanum variabile (1000 mg/kg) administered for 14 consecutive days accelerated the ulcer healing by 46% compared to a 55% effect of cimetidine. Also, at the dose of 1000 mg/kg, the EE inhibited the onset of duodenal lesions by 64%. The data suggest that the EE of Solanum variabile has a significant preventive, curative and duodenal anti-ulcer effect.