Bone loss leading to osteoporosis is common after the menopause and in the elderly but uncommon in normal young adults without predisposing factors. The risk factors usually associated with osteoporosis include a family history of osteoporosis or fractures, aging, prior diseases, sedentary lifestyle, low calcium intake, hypogonadism, vitamin D deficiency, smoking, and excessive alcohol consumption. However, the issue of drugs has to be considered in 'normal' individuals who present with osteoporosis or bone loss without predisposing genetic or other environmental factors. The list of drugs is extensive and includes, amongst others, glucocorticoids, thyroid hormone (excess), alcohol, medroxyprogesterone acetate, luteinizing hormone-releasing hormone agonists, anti-seizure medications, cyclosporine A, aluminium, lithium, and exchange resins. This paper reviews the pathophysiology and mechanisms of drug-induced bone loss, which includes osteoporosis and osteomalacia, and treatment concepts. Undoubtedly, physician awareness, appropriate investigation, careful prescribing, monitoring, and proper therapy for this eminently preventable side effect can preserve bone in the patients receiving bone-losing drugs.