A placebo-controlled, double-blind study was carried out over 4 months to evaluate two doses of synthetic human calcitonin (0.25 and 0.125 mg) given s.c. three times per week. Enrolled were 60 women, aged 56–82 years, who had experienced a vertebral fracture due to low-energy trauma within the preceding year. During active treatment there was within the first month a dose-dependent decrease of the indices of bone resorption (fasting urinary calcium and hydroxyproline excretions), whereas only the higher dose and a treatment period of 4 months produced a reduction of bone formation (serum osteocalcin). The bone mineral content (BMC) of the nondominant forearm was unchanged. Treatment with calcitonin also had significant, dosedependent, analgetic effects. The amelioration of pain was, in multivariate analyses, related to a reduction in parameters felt to be markers for bone resorption. In the placebo group there was a significant reduction of the BMC of the forearm but no changes of any of the biochemical markers for bone turnover and no improvement of pain. In conclusion, treatment with two low doses of calcitonin induced changes of the biochemical markers of bone turnover in a dosedependent manner. The analgetic properties of calcitonin were also of salient clinical importance. The knowledge derived from this study could be adapted to the dosage schedule in long-term trials in osteoporosis.