AIM: To study the bioequivalence and pharmacokinetics of doxycycline enteric-coated microsomes capsules and doxycycline tablets. METHODS: A single oral dose of 200 mg doxycycline enteric-coated microsomes capsules and doxycycline tablets was given to 20 healthy male volunteers in an open randomized cross-over test. The plasma drug concentration was determined by high performance liquid chromatography (HPLC) method. The relative bioavailability and bioequivalence of 2 doxycycline were calculated and compared. RESULTS: The pharmacokinetic parameters of doxycycline enteric-coated microsomes capsules and doxycycline tablets were as follows: c max: (3.65±0.81) μg·mL -1 and (3.65±0.73) μg·mL -1, t max: (2.5±0.3) h and (2.2±0.7) h, T 1/2ke: (21.48±3.20) h and (21.85±3.11) h, AUC 0→72: (72.18±22.68) μg·h·mL -1 and (72.06±21.08) μg·h·mL -1,AUC 0→∞: (81.44±24.94) μg·h·mL -1 and (81.82±23.19) μg·mL -1, respectively. The relative bioavailability of doxycycline enteric-coated microsomes capsules was (101.9±25.2)% compared with the tablet. Variance analysis and two one-sided t test were performed to parameters: c max, AUC 0→72 and AUC 0→∞. The results showed that the parameters were no significant statistical differences. CONCLUSION: The 2 preparations of doxycycline are bioequivalent.