The clinical features of vitamin A toxicity in a 7-year-old boy, a 16-year-old boy, and a 46-year-old man included vague skeletal pains and hypercalcemia. Experimental and clinical evidence indicates that hypervitaminosis A can cause bony resorption as well as periosteal calcification. Ingestion of excessive amounts of vitamin A should be considered in the differential diagnosis of hypercalcemia. Vitamin A preparations containing more than the minimum daily requirement for an adult (5000 units) per dose should be dispensed only by prescription.