Antidiarrhoeal effect of piperine was evaluated in castor oil and magnesium sulphate induced diarrhoea in mice. Effect of piperine was also studied on intestinal propulsive movement and intestinal fluid accumulation in mice. Piperine, at a dose of 5 to 20 mg/kg showed antidiarrhoeal activity in castor oil and magnesium sulphate induced diarrhoea. It has also produced antimotility and antisecretory activity in castor oil induced intestinal transit and intraluminal fluid accumulation in mice. These results suggest that piperine possesses antidiarrhoeal effect may be due to its antimotility and antisecretory effect.