Postburn changes in serum levels of Alterations in serum Calcium (Ca), Phosphates (Pi), alkaline-phosphatase (ALP), calcitonin (CT), parathyroid hormone (PTH) and 25-hydroxy Vitamin D (25 OHD) levels in 14 burn patients were studied. The results indicated: (1) Hypocalcemia and hypophosphatemia occurred during burn shock. Hypocalcemia was closely associated with the degree of burn and patient's condition. (2) Serum CT and PTH levels were significantly increased in severe burn patients compared with controls on day 1. Then the parameters tended to decrease to normal levels. (3) CT/Ca ratio or CT/Pi ratio might be a sensitive index to indicate the degree of burn and patient's condition.