In a multicentre, randomized, double-blind controlled trial comparing the low-molecular-weight heparin enoxaparin (40 mg) with a standard unfractionated heparin (Ca-heparin, 3 x 5,000 U) in deep-vein thrombosis prophylaxis in a high-risk group of 959 hospitalized medical patients, enoxaparin was at least as efficacious as standard heparin, with fewer adverse events.