The comparison of 20 untreated spasmophilic patients (2 men, 18 women) with 25 healthy subjects revealed no significant differences in vitamin D metabolite plasma levels or in other laboratory indexes of calcium metabolism except for ionized and cytosolic free calcium levels which were lower in the former group (P less than 0.01; P less than 0.001). After 3 months treatment with calcitonin and 25-hydroxyvitamin D there was a clear improvement in patient symptoms, no significant modification of 1,25-dihydroxyvitamin D levels and significant increases in 25-hydroxyvitamin D, cytosolic free calcium and urinary calcium (P less than 0.001, P less than 0.001 and P less than 0.01, respectively). We conclude that high plasma levels of 25-hydroxyvitamin D play an important role in restoring normal cytosolic free calcium levels and reducing clinical manifestations in spasmophilia.