Objective To discuss the influence of Saccharomyces boulardii on serum apolipoprotein levels in liver cirrhosis patients with spontaneous bacterial peritonitis (SBP).Methods 74 liver cirrhosis patients with SBP were selected and randomly divided into the observation group and control group.Patients in the two groups were given routine medical treatment such as liver protection and diuretic effect,correction of hypoproteinemia,anti-infection etc.Patients in the observation group were orally given Saccharomyces boulardii 0.5g for one time,two times daily for 4 weeks.The changes of serum apolipoprotein A1 and B levels in two groups were observed and compared,and the curative effect and safety were also observed.Results After treatment for 4 weeks,the serum apolipoprotein A1 and B levelsintwogroupswereobviouslyincreasedcomparedwithbeforetreatment (t =2.46,2.3 7,3.04,2.87,P ＜ 0.05or P ＜0.01),and the increase of observation group was much higher than that of control group(t =2.29,2.23,all P ＜ 0.05).Meanwhile,the total effective rate of the observation group (91.89％) was significantly higher than that of control group (72.97 ％) (x2 =4.57,P ＜ 0.05).3 cases and 5 cases of adverse reactions appeared in control group and observation group,the symptom was light and no serious drug adverse reaction(DAR) observed.The incidence rate of DAR between the two groups had no obviously statistical difference (x2 =0.14,P ＞ 0.05).Conclusion Saccharomyces boulardii has reliable curative effect and high security in the treatment of liver cirrhosis patients with SBP,the mechanism may be related with increasing the synthesis of apolipoprotein A1 and B in the liver and intestine,and increasing serum levels of apolipoprotein A1 and B.