Background and objective: Nevirapine is a highly active antiretroviral therapy in the management of Human Immunodeficiency Virus (HIV). Gastrointestinal disorders like diarrhoea, nausea, bleeding and vomiting are usually diagnosed in HIV patients as opportunistic infections. Hence, the impact of nevirapine on gastric ulcer, a gastrointestinal disorder, was studied using Wistar rats. Methods: Anti-ulcer activity of nevirapine was evaluated using cold restraint stress-induced, ethanol-induced[1] and pylorus ligation-induced[2] gastric ulcer models for acute ulceration; and acetic acid-induced ulcer model[3] for the chronic ulceration in Wistar rats. Chloral hydrate anaesthesia (300mg/kg) was administered intraperitoneally while nevirapine was administered orally. The animals were housed in a raised mesh bottom metal cages to prevent coprophagy and kept in environmentally controlled rooms (25±20C, 12hours light and dark cycle). The procedures were carried out by avoiding stress. Results: Nevirapine (9mg/kg, 18mg/kg and 36mg/kg ) showed significant (P<0.05) reduction in ulcer severity score and ulcer index as compared to the control in the models, with corresponding increase in percentage inhibition. Histopathological studies showed that nevirapine has a positive effect on the healing of gastric ulcer in the groups treated with the nevirapine compared with the control. The induced ulcers healed up in all the groups administered with nevirapine compared to what is found in the omeprazole group where manifestations of ulcer like inflammatory cells infiltration is still present. Interpretation and Conclusion: Nevirapine may possess highly therapeutic effect in the treatment and prevention of gastrointestinal complications that might come with the presence of HIV virus in patients.