Objective To observe the clinical effect of boulardii in the treatment of children with acute diarrhea .Methods 100 children with acute diarrhea were selected as the research subjects , they were randomly divided into two groups by computer blind grouping method .50 cases in the control group received conventional treatment,50 cases in the observation group were given boulardii treatment .The treatment effect,duration of diarrhea, stool frequency and incidence of secondary diarrhea were compared between the two groups .Results The total effective rate of the observation group was 96％,which was significantly higher than 80％of the control group (χ2 =6.061,P <0.05).The diarrhea duration of the observation group was (2.85 ±1.17) d,which was significantly shorter than(4.31 ±1.54)d of the control group(t=5.338,P<0.05).After treatment for 4 days,7 days,the stool frequency in the observation group were (2.63 ±1.04)/d,(1.87 ±0.95)/d,respectively,which were lower than those in the control group [(3.89 ±1.22)/d,(2.94 ±1.08)/d,t=5.558,5.260,all P<0.05].The incidence rate of secondary diarrhea of the observation group was 0％, which was significantly lower than 10％ of the control group(χ2 =5.263,P<0.05).Conclusion Boulardii in the treatment of children with acute diarrhea has significant clinical efficacy , it can accelerate the antidiarrheal speed , effectively prevent secondary diarrhea , it, is superior to conventional therapy .