To explore the antidiarrheal effect of different polarity extracts from Saposhnikovia divaricata in diarrhea rats and their regulatory roles on colonic expression of different aquaporin (AQP) subtypes,80 SD rats were randomly divided into normal group,model group,diphenoxylate group,petroleum ether fraction of S. divaricata group,ethyl acetate fraction group,n-butanol fraction group,aqueous fraction group,and total extracts group,with 10 rats in each group.Except for the normal group,all the other groups were given senna leaf decoction for 7 days.From the 8th day,rats in each group were given senna leaves in the morning and corresponding drugs in the afternoon for 7 days.The rats in the normal group and model group were given an equal volume of 2% Tween-80 solution.The feces of rats was observed,the electrolyte contents and the levels of diamine oxidase (DAO),tumor necrosis factor-α (TNF-α),and Na⁺-K⁺-ATPase in the serum were detected.Hematoxylin-eosin (HE) staining was applied to observe the pathomorphological changes of colon.The expression of different AQP subtypes was analysed by Western blot.The results showed that the petroleum ether fraction,n-butanol fraction and total extract of S. divaricata reduced the diarrhea index of rats,increased the contents of Na⁺ and K⁺ in serum and the activity of Na⁺-K⁺-ATPase in colon,reduced DAO and TNF-α in serum,improved colonic mucosal damage,and upregulated the protein expression of AQP-3,AQP-4 and AQP-8 in colon.The petroleum ether fraction of S. divaricata downregulated the protein expression level of AQP-9 in colon.Conclusion could be achieved that S. divaricata has obvious antidiarrheal effects,the petroleum ether fraction of S. divaricata and n-butanol fraction may well be the active sites for antidiarrhea,and they have different regulatory roles on different AQP subtypes in colon.