AIM:To evaluate the effect of antiviral agents on intrahepatic HBV DNA in HBeAg-positive chronic hepatitis B patients.METHODS: Seventy-one patients received treatment with lamivudine, interferon alpha (IFN-α2b) or sequential therapy with lamivudine-IFN-α2b for 48 wk. All subjects were followed up for 24 wk. Serum and intrahepatic HBV DNA were measured quantitatively by PCR. HBV genotypes were analyzed by PCR-RFLP.RESULTS: At the end of treatment, the intrahepatic HBV DNA level in 71 patients decreased from a mean of (6.1 ± 1.0) log10 to (4.9 ± 1.4) log10. Further, a larger decrease was seen in the intrahepatic HBV DNA level in patients with HBeAg seroconversion. Intrahepatic HBV DNA level (before and after treatment) was not significantly affected by the patients'HBV genotype, or by the probability of virological flare after treatment.CONCLUSION: Intrahepatic HBV DNA can be effectively lowered by antiviral agents and is a significant marker for monitoring antivirus treatment. Low intrahepatic HBV DNA level may achieve better efficacy of antivirus treatment.