Tacalcitol (1,24(R)-Dihydroxyvitamin D3; 1.alpha.,24R-Dihydroxyvitamin D3)promotes normal bone development by regulating calcium.Tacalcitol(1,24(R)-Dihydroxyvitamin D3; 1.alpha.,24R-Dihydroxyvitamin D3) modulates immunological and inflammatory processes. Tacalcitol induces nerve growth factor production in epidermal keratinocytes.