Rocaltrol is a synthetic form of vitamin D, specifically known as calcitriol, which is used primarily to treat conditions caused by low or dysfunctional levels of calcium in the body. This includes conditions such as renal osteodystrophy in patients with chronic kidney failure, hypocalcemia in patients undergoing dialysis, and hypoparathyroidism, where the parathyroid glands produce too little parathyroid hormone. Rocaltrol works by promoting calcium absorption in the intestines and retention in the kidneys, thereby increasing blood calcium levels. It also aids in the normal bone formation and maintenance. As with any medication, Rocaltrol should be used under the guidance of a healthcare professional to ensure proper dosage and to monitor for potential side effects.