Two experiments involving 32 growing pigs were conducted to evaluate various concentrations of corn oil, magnesium sulfate, and oat hulls as ameliorants in a high cornstarch-low protein ulcerogenic ration. The pig were slaughtered at the end of the respective feeding periods, and stomachs were evaluated for issue lesions. During a 40-day feeding period, additions of corn oil and of MgSO4 in the rations did not seem to affect development of gastric lesions materially. After a 42-day feeding period, neither 5.0% nor 10.0% concentration of oat hulls in the ration prevented formation of ulcers. Total stomach contents, free gastric HCI, and pH of stomach contents were measured in pigs slaughtered after 3, 6, 9, and 12 hours of fasting. Gastric HCI (mEq/L) differed significantly among pigs fed various rations and increased significantly with length of fasting. The pH of stomach contents did not differ among pigs given various rations, but decreased with length of fasting. Thus, corn oil, MgSO4, or oat hulls did not seem to significantly alter the ulcerogenic character of the high cornstarch-low protein ration.