It has been previously shown that Taraphochlamys affinis possessed anti-hepatitis B virus (HBV) activities. To identify the active ingredients, the total saponins (TSTA) were isolated from T. affinis and the inhibitory effect of TSTA on HBV in the duck HBV model was examined. The results showed that serum levels of DHBV-DNA decreased in all ducks treated with TSTA (1.0 and 2.0 g x kg(-1) x d(-1)) and lamivudine (3TC) (50 mg x kg(-1) x d(-1)) during treatment, but 7 days after the cessation of treatment (p7) with 3TC, the viral replication level returned to the pretreatment baseline. Contrariwise in ducks treated with TSTA, the effect of DHBV DNA inhibition lasted. Compared with model control group,the alanine aminotransferase (ALT), aspartate aminotransferase (AST) and duck hepatitis B surface antigen (DHBsAg) values of 1.0 and 2.0 g x kg(-1) x d(-1)-dose TSTA groups were significantly lower on 7, 14 days after the treatment (d7, d14) and p7, and at p7, the ALT and DHBsAg levels of 2.0 g x kg(-1) x d(-1)-dose TSTA group was significantly lower than that of 3TC group. Furthermore, significant histological improvement was noted in ducklings of TSTA treatment group 7 days after the withdrawal. The study results demonstrate that TSTA possesses potent anti-HBV activity.