As the primary link between brain and gut,autonomic dysfunction play a role in the pathophysiology of IBS.The aim of this study was to assess autonomic response to cold-water test and colon distension.Method:30 women with IBS and 20 healthy women participated.HAMA and HAMD were used to measure their anxiety and depression conditions.5-minite-short-time heart rate variability(HRV) spectral analysis were aseessed at baseline and after a cold-water test,just before and after a colon distention.Results:IBS-group showed a higher score in HAMA and HAMD(p<0.01) and showed a significant increase in the low frequecy band/high frequency(L/H) band ratio and a decrease in the high frequncy band power during the period just before and after colon distension(p<0.01 ),which was significantly different from controls.Conclusions:These findings support the notion that an abnormal autonomic nerverse activities responsing to visceral and psychological stimuli may play a role in the pathophysiolgy of IBS.