Enoxaparin (Clexane), Lovenox) is a low molecular weight heparin (LMWH) that has been widely used in the prevention of venous thromboembolism (VTE) in surgical patients. More recently, with the recognition of the high incidence of VTE in acutely ill medical (nonsurgical) patients, enoxaparin has been evaluated for thromboprophylaxis in this patient population. Subcutaneous enoxaparin 40 mg once daily has shown efficacy in the short-term thromboprophylaxis of VTE in nonsurgical patients with severely restricted mobility due to acute illness in well controlled clinical trials. The drug is at least similar in efficacy to unfractionated heparin (UFH) and its pharmacological profile allows once-daily administration, in contrast to the twice- or three-times-daily administration required with UFH. The tolerability profile of enoxaparin is also similar to that of UFH, except that the incidences of local haematomas and increased liver enzymes are lower with enoxaparin. The optimal duration of prophylaxis in nonsurgical patients is currently being evaluated and the results of extended prophylaxis with enoxaparin evaluated in the EXCLAIM (EXtended CLinical prophylaxis in Acutely Ill Medical patients) trial are awaited with interest. Currently, short-term enoxaparin appears to provide a cost-effective treatment alternative to UFH for VTE prophylaxis in nonsurgical patients.