We compared the effects of somatostation and ranitidine on treatment of stress ulcer on rats in an experimental study. Three groups were created; sham group, ranitidine group and somatostation group. Gastric mucosal damage index was measured in each group and Mann-Whitney U test was used for statistical analysis. Statistically, the mucosal damage index was signiticantly higher in thesomatostatin group comparing the control group (p>0.001) and also in the control group comparing the ranitidine group (p<0.05). Ranitidine was more effective in the treatment of stress ulcers than somatostatin (p<0.001 ), besides the gastric mucocasal damage was enlarged by administration of somatostatin. We assume that this may be explained by the reduced splanchnic blood flow after the administration of somatostatin to the stressed animals.