Ergocalciferol is commonly known as Vitamin D2. Ergocalciferol is an inactivated vitamin D an alog. It is a form of vitamin synthesized by some plants in the presence of UVB light. Vitamin D2 helps body in absorbing calcium. Ergocalciferol is fat-soluble vitamin which prevents Rickets disease. Vitamin D2 is used to treat hypoparathyroidism.