Three antihemorrhagic factors (AHF-1, AHF-2 and AHF-3) were purified from the serum of H. edwardsii, a mongoose, by a combination of gel filtration on a Sephadex G-200 column and high performance liquid chromatography with a TSK gel DEAE-5PW column. Each of the purified antihemorrhagic factors showed a single band on polyacrylamide gel disc electrophoresis. The three antihemorrhagic factors inhibited the hemorrhagic activity of HR 1 and HR 2, the hemorrhagic principles from the snake venom of Trimeresurus flavoviridis Okinawa. AHF-1, AHF-2 and AHF-3 were stable at temperatures from 0 degrees to 60 degrees C and at pH values between 2.0 and 11.0. The same molecular weight (65,000) was obtained for the three antihemorrhagic factors. No precipitin lines were found for the purified antihemorrhagic factors with the venom of T. flavoviridis Okinawa and its hemorrhagic principles, HR 1 and HR 2.