Studies of bone and mineral metabolism were made in 22 patients with chronic alcohol abuse and varying degrees of liver damage. None of the patients had clinical evidence of metabolic bone disease, but quantitative bone histology showed that six had osteoporosis, three osteomalacia, and two osteoporosis and osteomalacia combined. Trabecular bone volume (TBV) tended to be reduced in relation to age, and there was histological evidence of reduced bone formation particularly among the patients with osteoporosis. Multivariate analysis of the relevant variables showed that the major determinants of age-adjusted trabecular bone volume were the serum concentration of albumin and the dietary calcium. The presence of osteoporosis was related to the state of liver function and the type of alcohol habitually consumed, and was a particular feature of patients with severe liver disease and those who only drank spirits. Six patients (five with osteoporosis) had biochemical evidence of hyperparathyroidism, but none showed histological evidence of increased bone resorption or of osteitis fibrosa. In four patients the development of hyperparathyroidism was probably related to underlying magnesium deficiency. Serum calcidiol tended to be reduced and was directly related to the state of liver function; four patients had reduced or low normal serum concentrations of calcitriol. In only three patients could the development of osteomalacia be related to vitamin D deficiency; in two patients the cause of the osteomalacia was obscure. Significant changes in bone structure and mass appear to be common among heavy drinkers even in the absence of clinical metabolic bone disease. These skeletal abnormalities are likely to be relevant to the increased fracture risk associated with heavy drinking.