This work considers how, in the field of stomatology, haemorrhagic phenomenous may occur which can even be serious, due to the blood coagulations defects. Only an accurate anamnesis can reveal the pathology and if it is necessary, to undertake to do specific tests and analysis. When the patient is suffered from haemorrhages, it is indispensable to associate with local therapy a general treatment prescribed by the haematologist. We underline the importance of the existence of specialized dental centers for the prevention and the treatment of oral pathologies in patients suffered from blood defects or in patients in anticoagulant therapy which cooperate with specialized haematologic centers. Even in our department, the patients with haemorrhagic diathesis are treated in collaboration with the specialist. We have shown through the presentation of two clinical cases the results who we have reached with the application of our pre-operation protocol