Abstract: OBJECTIVE To study the effect of large doses hemocoagulase Agkistrodon acutus on the fibrinogen level in rabbit, to provide a reference for clinical application. METHODS The 30 rabbits were randomly divided into 5 groups and were injected with different doses of hemocoagulase Agkistrodon acutus respectively, the plasma fibrinogen level were examined after administration. RESULTS The hemocoagulase Agkistrodon acutus with 0.2-1.0 U·kg^-1 doses resulted in the significant decrease of the plasma fibrinogen level of rabbits. The depletion of plasma fibrinogen was first occurred in individual rabbit at 0.4 U·kg^-1 doses, and while the doses were increased above 0.6 U·kg^-1(include 0.6 U·kg^-1). The depletion of plasma fibrinogen was occurred in all rabbits. CONCLUSIONS The large doses hemocoagulase Agkistrodon acutus have significant effects of decreasing the plasma fibrinogen level of rabbits.