No satisfactory treatment is available for metabolic bone disease associated with primary biliary cirrhosis. On the basis of the similarities to postmenopausal osteoporosis, the rationale exists for calcitonin to be tested in clinical studies in patients with primary biliary cirrhosis-associated osteoporosis. We evaluated the effect of calcitonin on bone metabolism and mineral density in 25 women with primary biliary cirrhosis and severe osteopenia. After 6 mo of observation, patients received a synthetic calcitonin or a control treatment consisting of less than one hundredth of the recommended dose of porcine calcitonin. The two treatments were administered in sequence to each patient for two 6-mo periods, with a 3-mo washout between them, according to a crossover design. After the observation period, oral calcium supplementation was started. Bone mineral density was measured by dual-photon absorptiometry of the lumbar spine at study entry and at the beginning and the end of each treatment period. During the observation period bone mineral density fell by 3.5% whereas during the following 6 mo it increased in both the patients who received calcitonin (4.3%) and those who received the control treatment (4.9%). Conversely, after the crossover, bone mineral density decreased during both calcitonin (-2.7%) and control treatment (-2.9%). A significant difference was observed between the two periods but not between the two treatments or between the two sequences of treatment administration. In conclusion, our findings indicate that parenterally administered calcitonin for 6 mo is ineffective in halting bone loss in patients with primary biliary cirrhosis-associated metabolic bone disease, whereas calcium supplementation may have a transient beneficial effect.