Aim To explore the effects of substance P ( SP) and calcitonin gene-related peptide ( CGRP) on the occurrence and development of inflammatory bowel disease ( IBD) ． Methods The IBD rat model was generated by chemical induction with trinitrobenzene sulfonic acid ( TNBS) ． The expression of SP and CGRP in the colon tissues was determined by real-time RT-PCR． Results With the development of pathological changes ( on days 3，7) ，the expression level of SP and CGRP in the colon was significantly increased，and then followed by a decline and gradual return to normal levels ( on days 21，28) ． Generally speaking，the expression of both SP and CGRP was positively related to the occurrence and development of IBD． Conclusions The results of this study revealed that the neurotransmitters，SP and CGRP，play an important role in signal transduction in the inflammation and repair of inflammatory bowel disease