To explore the regulatory effect of Plantago asiatica L.on expressions of AQP8 in colon tissue and serum inflammatory factors in Senna -triggered diarrhea rats.60 Sprague-Dawley male rats were randomly divided into normal group,model group, hydrochlorothiazide group ( 9 mg/kg ), and high,middle,and low Plantago asiatica L. groups ( 3.8,1.9,0.95 g crude drugs / kg,respectively),with 10 rats distributed in each group.Intragastric administration of Senna ( 20 mL/kg) was implemented in the morning for 5 groups except of normal group,which was implemented by same dose of distilled water.In the afternoon,each treatment group was given corresponding drugs,while normal group and model group were given same dose of distilled water for 14 consecutive days.Defecation of rats was detected during administration.At the end of experiment,samples collected from serum and colon tissue of rats were provided for content detection of tumor necrosis factor-α (TNF-α),interleukin-6 (IL-6) and C-reactive protein (CRP);HE staining was applied to observe the pathomorphological changes,while immunohistochemical method and Western blot were used to detect protein expressions of AQP8 in colon tissue.The results showed that every group of Plantago asiatica L. changed the fecal characteristics of rats,and the stools were basically formed;Contents of serum TNF-α,IL-6 and CRP decreased,and pathological damage of colonic mucosa was reduced,and expression of AQP8 protein was elevated.Conclusion could be achieved that Plantago asiatica L. can prevent diarrhea induced by Senna,and its mechanism may be related to inhibition of inflammatory reaction,repair of pathological damage of colonic mucosa,up-regulation of AQP8 expression and promotion of water and fluid metabolism.