OBJECTIVE To investigate the effects of the Labrasol on the function of the intestinal P-glycoprotein(P-gp).METHODS The isolated rat intestinal membranes were used to study the effects of Labrasol on the transportation of Rhodamine123(a subtrate of P-gp) and Lucifer yellow(non-subtrate of P-gp )by ussing chamber.RESULTS Labrasol in low concentration(0.05%～0.075%) can affect the transportation of Rodamine123,but has no effect on Lucifer yellow in ileum and colon.CONCLUSION Labrasol can inhibit the function of P-gp in ileum and colon, thereby increasing intestinal absorption and bioavailability of various drugs.