AlM To study the inhibited effect of atractylon on HBsAg and HBeAg in the cultured hepatocarcinoma cell line 2215 (HepG2) which was genetransfered with hepatitis B virus(HBV) and its toxicity.MEHTODS The 2215 cells were treated with the varied concentration of Atractylon below the maximum nontoxic concent ration for 8 d.Culture fluid was collected and the contents of HB-sAg and HBeAg were determined by using radioimmunoassay kit respectively.RFSULTS The TC50 of atractylon were 500 mg· L-1.The maximum nontoxic concentration (TC0) were 250 rmg·L-t.In nontoxic concentration (250 mg· L-1) , the inhibitions of Atractylon on HBsAg and HBeAg were 54.5% (IC50 =211.4 mg·L-1) and 59.98% (IC50 =185.3 mg·L-1), respectively (P <0.01).CONCLUSION Atractylon is effective in inhibiting HBV replication in vitro.