A stabilized liquid preparation of a protease which activates blood coagulation Factor VII or of its proenzyme is herein described. The preparation also contains one or more compounds selected from the group consisting of ornithine, diaminopimelic acid, agmatine, creatine, guanidinoacetic acid, acetylornithine, citrulline, arginoinosuccinic acid, tranexamic acid and epsilon-aminocaproic acid or their salts and has a pH of 2 8.