OBJECTIVE: To study pharmacokinetics of valaciclovir hydrochloride tablets and to evaluate the bioequivalence of test and reference tablets. METHODS: In a two-period cross-over design test, 18 healthy volunteers were given a single oral dose of 600 mg test valaciclovir hydrochloride and 600 mg reference formulations respectively. Plasma concentrations of acyclovir were determined by HPLC method. The pharmacokinetic parameters of the two formulations were calculated and analyzed statistically. RESULTS: The main pharmacokinetic parameters of test vs. reference valacyclovir hydrochloride tablets were as follows:tmax(1.69?0.25)h vs. (1.72?0.26)h, Cmax(3.34?0.58) ?g?mL-1 vs. (3.40?0.49)?g?mL-1, t1/2(2.73?0.31)h vs. (2.97?0.33)h, AUC0～14(11.22?2.21) ?g?h?mL-1 vs. (11.12?1.90)?g?h?mL-1, AUC0～∞(11.76?2.15) ?g?h?mL-1 vs. (11.61?1.86)?g?h?mL-1, respectively. As compared with reference formulation, the relative bioavailability of test formulation was (101.06?11.72)%. CONCLUSION: The two preparations are bioequivalent.