In 2000, the French authorities licensed the low-molecular-weight heparin (LMWH) enoxaparin for thromboprophylaxis in acutely ill medical patients. However, the lack of official recommendations for this group of patients has contributed to inappropriate use of LMWH. The recent College of Internal Medicine of Paris (CIMOP) and Données Epidémiologiques chez les Patients A Risque Thromboembolique (DEPART) epidemiological studies have confirmed that LMWH is prescribed for 32% of medical inpatients and up to 44% of outpatients. However, they highlight overuse in elderly bedridden patients without acute illness and underuse in patients with severe infections or cardiopulmonary disease. Guidelines are urgently needed to encourage French physicians to target thromboprophylaxis for medical patients who are genuinely at high risk of thromboembolic disease and to prescribe the appropriate dose and duration of therapy.