Seven patients with diarrhoea-predominant irritable bowel syndrome were studied during control, sham stimulation and acupoints (ST 36 and P 6) stimulation periods. Rectal tone, compliance and perception to rectal balloon distension were assessed with a barostat apparatus. Acustimulation at ST 36 and P 6, but not sham stimulation, significantly increased the threshold of rectal sensation of gas, desire to defecate and pain, as compared to control period. However, rectal tone and compliance were not significantly affected during transcutaneous electrical acustimulation.