Abstract: [Objective]To investigate the influence and curative effect of Saccharomyces Boulardii combined with Lactulose on serum enteric neurotransmitter indexes of children with functional constipation(FC).[Methods]86 cases of children with FC,who were given medical treatment in pediatric outpatient department,were selected,and divided into observation group and control group at random,with 43 cases of children in either group.The children in two groups were given plenty of water,diet adjustment,defecation exercise and other basic medical treatment.The children in control group were given 5 ml Lactulose oral solution per time,twice a day,through the mouth,while the children in observation group were additionally given 0.25 g Saccharomyces Boulardii powder per time,once a day,with warm boiled water,for 6 weeks' course of treatment.The changes of serum nitric oxide(NO)and somatostatin(SS)of serum enteric neurotransmitter indexes of children in two groups before and after medical treatment were observed,and the clinical curative effect and drug adverse reaction(DAR)were compared as well.[Results]4 and 6 cases of loss to follow up appeared on children in control group and observation group respectively,and after comparing the loss rates to follow up of children in two groups,no statistical differences appeared(P＞0.05).After 6 weeks' medical treatment,NO and SS indexes of children in two groups obviously declined than before,and serum NO and SS indexes of children in observation group were much lower than those in control group(P＜0.05).Total clinical efficiency of children in observation group was much higher than that in control group(χ²=4.79,P＜0.05).[Conclusion]Saccharomyces Boulardii combined with Lactulose had favorable curative effect on children with FC with high security,whose mechanism may have close effect on reducing serum NO and SS indexes,improving gastrointestinal motility and relieving constipation symptom.