Vit D supplementation tolerance is usually considered as good and over-dosage risks are low, however these studies were conducted more than 30 years ago, and as far as we know, there is no study about calcium urinary excretion kinetics after intake of a 100 000 IU vial of cholecalciferol (Uvedose®). When 25 OH vitamin D serum concentrations exceeds 200 ng/mL, which is very rare in daily practice, toxic effects of Vit D may theoretically be observed, particularly hypercalcemia and hypercalciuria.