Two hundreds patients of peptic ulcer diagnosed by fiber-gastroscope treated with Yuyang powder (YYP) was observed and compared with patient treated with cimetidine for control. Results showed that the curative rate of YYP on peptic ulcer was 88.1%, the total effective rate was 96%, similar to that of cimetidine. But the difference of recurrence rate (19.1% for YYP and 46% for control) between the two groups was very significant. Animal experiment revealed that the protective action of YYP with high dosis on gastric mucosa in peptic ulcer and gastritis was superior to that of cimetidine, its has the double effect of both strengthening protective factors and weakening aggressive factors of gastric mucosa. Acute toxicologic test indicated that YYP has no toxic effect and was safe in clinical practice.