The present study was done to evaluate the effect of cetraxate on the gastric secretion of rats with pylorus ligation. We determined the gastric volume, acid output, total protein, mucoprotein and pepsin concentration of gastric juice 24 hours after administration. The following results were obtained. The gastric volume was decreased than control group. 2. The acid output was decreased than control group. The total protein and mucoprotein were markedly increased in spite of low dosage administration of cetraxate. 4. The pepsin concentration was not changed.