AtoD Drops includes Vitamin D3, Vitamin A & Vitamin E. Whose purpose it is to strengthen your immune system, your vision. Your heart, lungs, and other organs operate correctly with the support of vitamin A. While vitamin D3 is required to compensate for a lack of vitamin D3 in our bodies, particularly for infants & toddlers. It makes bones and muscles healthier. Vitamin E is an important fat-soluble nutrient.