Objective To research the mechanism of Turbid-Transforming Toxicity-Relieving Stomach-Regulating Formula（TTSF）on Precancerous lesions associated with chronic atrophic gastritis（CAG）.Methods Totally 259 cases of precancerous lesions associated with CAG were randomized into the treatment group of 137 cases and control group of 122 cases.The treatment group was given TTSF one dose daily.The control group was given Weifuchun Tablets three times daily.One treatment course lasted for 3 months and both groups were treated for 2 treatment courses.The performance under endoscopy

pathology and Helicobacter pylori（Hp）infection was observed before and after treatment.The gastric pH value

free acid

pepsin

mucus value and bile acid value was detected.Results The improvement rates of endoscopy and pathology in the treatment group were superior to those in the control group（P < 0.05 or P < 0.01）.The negative rate of Hp in the treatment group and control group was 89.6% and 63.1% respectively

with a significant difference between groups（P < 0.01）.There was a significant difference between before and after treatment in the pH value

free acid

pepsin

mucus value and bile acid value in both groups（P < 0.05）

especially in the treatment group（P < 0.05）.Conclusion TTSF can improve the performance of endoscopy and pathology

eradicate Hp and recover the secretion of gastric acid.