Objective: To observe the level of serum CGRP and 5-hydroxytryptamine in animals model of irritable bowel syndrome treated with sheng yang yi wei decoction.Methods: 70 SPF SD rats were divided randomly into normal control group,model group,dicetel group,sheng yang yi wei decoction group(low dosage,moderate dosage,high dosage).The rat model of irritable bowel syndrome was made by binding stress and clasping their tails.group.Changes of diarrhea rate were observed in these groups．Radioimmunoassay was used to detect the level of CGRP and 5-HT in plasma．Results：The diarrhea rates in group were decreased after treatment,and had the statistics significance in comparison with model group and dicetel group(P<0.05)．The contents of 5-HT in plasma in model group were higher than those in normal control group,while the levels of CGRP in model group were slighly lower than those in normal control group(P<0.05).After treatment,the contents of 5-HT in plasma in dicetel group and sheng yang yi wei decoction group were markedly decreased than those in model group(P<0.05),while the levels of CGRP had no statistics significance among all groups(P>0.05).Conclusions: Sheng yang yi wei decoction can markly alleviate the symptom of diarrhea,inhibit 5-HT synthesis and secretion in animal model of irritable bowel syndrome,while it does not effect the levels of CGRP.