A questionnaire about the use of anabolic steroids (AS) was distributed in weight-training and sports centre's and was completed by 157 persons. In the group of 138 men, 85 had employed AS but only 60% had employed preparations registered in Denmark. In the group who consumed AS in connection with intensive training periods, average weights and heights were found lower at the commencement of the training and greater increase in weight in connection with training. In the group who consumed AS, participation in competitive sports was greater and higher protein supplements and more supplementary medicine were observed. The average maximal 24 hour dosage of AS was ten times greater than that recommended therapeutically and this dosage was consumed during approximately 1/3 of the year. Side-effects were such that 25% of the men consulted their doctors. Less than half of the consumers of AS had sought information about the effects and side-effects and only 40% had consulted their own general practitioners which suggests a considerable illegal market. An important aspect of the prophylactic activity appears to be information about the injurious effects of AS consumption which appears to be widespread in Denmark together with intensive muscular training.