Abstract:Objective: To explore the effect of vinegar processing Cyperus rotundus on the expression and function of P-glycoprotein(P-gp)in Caco-2 cells. Method: The function of P-gp in Caco-2 cells was measured by FCM and the expression was by immunohistochemistry after the interaction between the cell(2×105/mL) and the medicine of concentration(5%,10%,20%). Result: The low, medium, high concentration of crude C. rotundus could increased 8.25%,9.57%,16.84% of the accumulation of digaoxi,vinegar processing C. rotundus could increase 22.44%,29.12%,33.09% of the accumulation of digaoxi.Serum containing crude and vinegar processing C. rotundus could remarkedly increase the accumulation of digaoxi and decrease the positive rate of P-gp's expression. Conclusion: C. rotundus after vinegar processed can promote the function of inhibiting the expression and function of P-gp in Caco-2 cells.