Cholecalciferol, also known as vitamin D3 and colecalciferol, is a type of vitamin D found in food and used as a dietary supplement. As a supplement it is used to treat and prevent vitamin D deficiency including rickets.  It is also used for familial hypophosphatemia, hypoparathyroidism that is causing low blood calcium, and Fanconi syndrome. It is taken by mouth. 

Vit D3 Cholecalciferol is used in the treatment of nutritional deficiencies.
How it works:
Vit D3: cholecalciferol provides essential nutrients

Excessive doses can result in vomiting, constipation, weakness, and confusion. Other risks include kidney stones. Normal doses are safe in pregnancy. It may not be effective in people with severe kidney disease. After being converted into 1, 25-dihydroxyvitamin D, it works by increasing the uptake of calcium by the intestines. Food in which it is found include some fish, cheese, and eggs.