Abstract: To determine the relationship between the effect of wuzhi capsules on the blood concentration of tacrolimus as compared to diltiazem and with regard to cytochrome P450 (CYP)3A5 gene polymorphisms, 170 patients who underwent renal transplantation from November 2014 to March 2018 and used tacrolimus combined with diltiazem 30 mg bid were selected in this study retrospectively. Patients were divided into an observation group (105 patients) and a control group (65 patients) according to whether they used wuzhi capsules after the operation. The polymorphisms of CYP3A5*3 were determined and the effect of wuzhi capsules on the blood concentration of tacrolimus, as compared with that of diltiazem was determined in patients with different CYP3A5*3 genotypes. This study complies with relevant ethical norms. The results show that compared with diltiazem, an increase of tacrolimus C₀/D was significantly correlated with the patient's CYP3A5*3 genotype in both the self-control and the control group. CYP3A5 expressers in the observation group were able to increase the tacrolimus C₀/D by about 76.8% by replacing the wuzhi capsules with diltiazem, but this effect was not observed in CYP3A5 non-expressers. In CYP3A5 expressers wuzhi capsules had a greater ability relative to diltiazem to increase the blood concentration of tacrolimus.