Complications observed in 51 patients receiving corticosteroids for greater than 1 year for asthma and other chronic pulmonary diseases were compared retrospectively with 31 control patients who had never been on corticosteroids. The prevalence of Cushingoid features (P less than .005), ocular complications (cataracts and glaucoma, P less than .025), and skeletal complications (compression fractures of vertebrae, aseptic necrosis of the femoral head, and osteopenia, P less than .005) in the study group was significantly higher than in the control group, as was the prevalence of total complications (P less than .005). Multiple regression analysis demonstrated that serious ocular and skeletal complications were directly proportional to the total lifetime dosage of corticosteroids. The high toxicity of steroid therapy should give further impetus to the formulation of ways to reduce or avoid steroid complications.