Abstract: Coagulation factor Ⅺ(factor Ⅺ,FⅪ)deficiency is a kind of hereditary hemorrhagic disease. Lack of FⅪ can cause lack of thrombin and high fibrinolytic activity, which leads to increased bleeding. Bleeding always happens in oral and nasal mucosa with high fibrinolytic activity in patients, and is often associated with trauma and surgery. This paper reported a case treated in China-Japan Friendship Hospital. The patient bled repeatedly after tooth extraction and was controlled with insertion of a tela iodoformum. The final diagnosis of the patient was coagulation factor Ⅺ deficiency and the bleeding was eventually stopped by plasma input.

Key words: Hemorrhage, Tooth extraction, Coagulation factor Ⅺ, deficiency