The major risk of oral anticoagulant therapy is haemorrhage potentially affecting all organs. Bleeding in the central nervous system is a rare but severe complication of anticoagulant therapy. This study aimed to analyse a series of intracranial haemorrhages. This series from the Regional Pharmacovigilance Center of Amiens included spontaneously reported and retrospectively collected cases from January 1999 to December 2000. During this period, 38 cases of intracranial bleeding possibly related to oral anticoagulant administration were reported; 19 women and 19 men, median age 69.5 (29 to 87) years. In 34% of the cases, patients died and in 18% neurologic sequelae were still present at the time of the evaluation. In 21 cases (62%), the INR (International Normalized Ratio) was higher than the therapeutic range recommended for the indication. Among the most frequent risk factors, hypertension and recent minor trauma are highlighted in this series. In 17 cases, oral anticoagulants were associated with potentially potentiating drugs. Mental status changes or headache were prominent early symptoms which had often been present for days. Our data confirm that anticoagulant-associated intracranial haemorrhages are not rare, can be severe, potentially fatal and are probably underestimated by physicians. The fact that more than 50% of patients in this series were overanticoagulated at the time of bleeding suggests that many cases of intracranial haemorrhage could be prevented by improved anticoagulation control. Epidemiological studies are needed in order to prospectively evaluate the incidence of this type of complication and its avoidance. The value of anticoagulation clinics can be discussed.