Previous studies of Nigerian children with rickets demonstrated the superiority of calcium over vitamin D in producing healing. It is not known whether the addition of vitamin D to calcium will produce a better response to treatment than calcium alone in Nigerian children. A previous study suggested the possibility that vitamin D may augment the effect of calcium. We will compare the response of rickets to calcium with and without vitamin D. In addition, very little human data clearly demonstrates the effect of supplemental vitamin D on calcium absorption. We will assess whether oral vitamin D increases the already high calcium absorption even further.