OBJECTIVE:To investigate the acid rebound in proton pump inhibitors (PPIs) and its influential factors. METH-ODS:Totally 109 patients who treated with PPIs for 1 month in our hospital during Jan.-Dec. 2015 were collected,and telephone visit was conducted after 1 week withdrawal to the data of dyspeptic symptoms were input and scored by modified Glasgow Dyspepsia Sere-rity Score,then divided into no phenomenon group(<5 scores)and acid rebound in proton pump inhibitors group(≥5 scores). All patients were classified by basic diseases,age,gender,whether smoking and alcohol drinking,and phenomenon of acid rebound in PPIs were observed and analyzed. RESULTS:Totally 91 patients were observed,49 were classified as acid rebound in PPIs group. χ2 test showed elderly patients(χ2=5.350,P=0.021)and people with smoking and alcohol drinking(χ2=4.351,P=0.037)were associat-ed with the increased risk of acid rebound in PPIs;exclusion of the effects of gender and basic disease,Logistic regression analysis showed the risk of acid rebound in PPIs in elderly patients were 5.708 times to non-elderly patients [OR=5.708,95%CI(1.946, 16.746),P=0.002];people with smoking and alcohol drinking was 15.281 times to non-smoking and alcohol drinking [OR=15.281, 95%CI(2.748,84.965),P=0.002],the difference was statistically significant(P<0.05). CONCLUSIONS:Parts of patients show ac-id rebound after stopping PPIs,while elderly patients and patients with smoking and alcohol drinking are the high-risk population, which should be paid attention to.