Gastric ulcers are common conditions that affect a large percentage of people worldwide. Modern medications have numerous negative consequences of treating illnesses as well as being costly. Therefore, the purpose of our study was to examine and compare the effects of mastic gum aqueous extract (100, 200, and 300 mg/kg of body weight) on the rats suffering from stomach ulcers. Five groups of thirty rats were created:  group one was served as a negative control and the second group with the gastric ulcers was kept as the positive control group. The other three groups with gastric ulcer were received the three different doses of mastic aqueous extract. In comparison to the positive group, the treated groups with the mastic aqueous extract exhibited a substantial improvement in pH values, an improvement in ulcer regions, and an increase in healing rate. In addition, the improvement in the activities of the antioxidant enzymes CAT, GPx, and SOD. Based on this results, we deduce that aqueous mastic extracts at varying concentrations (100, 200, and 300 mg/kg body weight) protect rats' stomachs from developing acute experimental stomach ulcers.