Among iatrogenic complications of oral anticoagulation, hemorrhagic complications are the most frequent and potentially lethal. The major hemorrhagic risk is the intensity of anticoagulation. A decrease of this risk is obtained with tapering of INR. Age, sex, anticoagulant therapy, and other personal risk factors as duration of anticoagulation, are factors not admitted by all the authors. Our experience at Hôtel-Dieu University Hospital and the literature data provide evidence that patient follow-up in a specialized center should decrease the incidence of hemorrhagic complications.