Background. Urtica simensis has been used for the treatment of peptic ulcer disease in Ethiopian folkloric medicine by drinking its juice after boiling the semicrushed leaf. To our latest understanding, no in vivo study was available regarding its antiulcer activity. The present study was done to appraise the ulcer-protective and ulcer healing activity of hydromethanolic crude extract of leaf of U. simensis in rats. Methods. Preliminary qualitative phytochemical screening and oral acute toxicity were carried out using a standard protocol. To validate U. simensis in vivo antiulcer potential pyloric ligature, cold restraint stress and acetic acid-induced ulcer models were employed. The extracts (100, 200, and 400 mg per kg of body weight per day), standard treatment (omeprazole 20 mg/kg/day), and vehicle (distilled water 10 ml/kg/day) were given to treatment, positive, and negative controls by oral gavage, respectively. Parameters were then evaluated accordingly after the humane scarification of rats. Results. Any sign of toxicity was not observed in the oral acute toxicity test. The crude extracts exerted a significant (
P
<
0.05
) inhibition of ulcer risk compared to the negative control. In the pylorus ligation-induced ulcer model, its antisecretory activity was in a dose-dependent manner. The highest gastroprotective effect (67.68%) was exhibited by the 400 mg/kg/day dose of 80% methanolic crude extract. Regarding the chronic ulcer model, treatment at a dosage of 100, 200, and 400 mg/kg/day cures ulcers by 33.54%, 58.33%, and 67.07%, respectively, as compared to the negative control groups remarkably. Conclusion. The findings of the present study confirmed the safety and a promising in vivo ulcer healing and antiulcerogenic activity of U. simensis, thus supporting the traditional claim. In-depth investigations on the plant, however, are highly recommended.