28 patients with progressing painful bone metastases (18 breast cancer, 9 myeloma and 1 low grade lymphoma) received pamidronate 60 mg by 24 h continuous infusion for at least 2 courses (range 2-12). In patients urinary calcium and hydroxyproline excretion significantly decreased in relation to diminution of bone resorption. 9 of 18 breast cancer patients and 8 of 9 evaluable patients with myeloma had symptomatic improvement. Sclerotic areas of previously lytic lesions appeared in 8 breast cancer patients and in 1 myeloma patient. Transient fever developed in 1 patient and local phlebitis in 2. Among the 28 patients, 15 did not receive any anticancer treatment or have any change of the anticancer therapy during pamidronate administration. Of 7 with breast cancer, 4 had an improvement of symptoms and 4 sclerosis on radiographs. Impressive control of symptoms was the major feature of 8 myeloma patients, but only 1 had radiographic sclerosis.