Myrtus communis subsp.is a plant which is traditionally used for the treatment of ulcer and diarrhea in Algeria. The aim of the study is to evaluate the antiulcer activity of aqueous extract of Myrtus communis subsp (AEMc). Fasted rats treated with 96% ethanol (0.5 mL) to induce gastric ulcer, were pretreated orally with AEMc extract from leaves at different doses (400 and 600 mg/kg body weight (BW) and Omeprazole (20 mg/kg) and distilled water were used as a positive and negative control respectively. The results showed that the pre-treatment with AEMc decreased significantly the ethanol gastric ulcer index value and preserved the integrity of the gastric mucosa by preventing the mucosal ulceration caused by ethanol. The AEMc prevented alcohol-induced decrease in stomach antioxidant enzyme activities such as catalase, and superoxide dismutase. Total reduced glutathione and malondialdehyde tissue contents were also reversed in AEMc-pretreated rats when compared with the negative control group