Abstract: ABSTRACT: OBJECTIVE To access the ratio of WAC and TAC in the combination therapy by evaluating the interaction between the two drugs in healthy volunteers in order to provide the basis for clinical rational drug combination therapy. METHODS The influence of single dose WZC on the TAC blood concentration will be evaluated on 8 healthy volunteers. They will be given WZC after being orally administrated TAC, and the blood concentration of TAC will be evaluated. Then the influence of multiple doses of WZC on TAC blood concentration will be studied on 40 healthy volunteers, which were divided into 5 groups randomly. Different doses of WZC will be administrated 5 min later than the TAC. and the blood concentration of TAC will be evaluated before and at different time points after the WZC administration. RESULTS The pharmacokinetic parameters of TAC in healthy volunteers after co-administrated different doses of WZC were obtained, T_max=(3.125±1.356)h, C_max=(43.539±10.656)ng·mL^-1, AUC_0→t=(459.3±114.2)ng·h·mL^-1, C_{12 h} or C_{24 h} was maintained at 5~10 ng·mL^-1, CL/F ration has fallen from 51.67% to 27%. CONCLUSION The blood concentration of TAC increased when being co-administrated with WZC. The TAC dose for the organ transplant patient could also be decreased when WZC were used together. Therefore, by combined with WZC, the economic benefit could be achieved via reducing the medical expenses of TAC for the organ transplant patient.