Vitamin AD is generally recommended to be taken half an hour after a meal or immediately after a meal, both of which can achieve good results. Vitamin AD is a fat-soluble vitamin that can be dissolved in fat, and the high fat content in the stomach after a meal can improve the absorption rate of vitamin AD. Vitamin AD deficiency is common in children, and vitamin A deficiency can easily cause night blindness in children, or dry eyes, affecting vision development. Vitamin D deficiency, which is also common in children, can cause rickets in patients. Therefore, vitamin AD supplementation is clinically important for the growth and development of children. It is usually recommended that children take it after feeding or eating. Vitamin AD has certain contraindications and the need to take it must be decided in consultation with a medical professional, taking into account the patient’s own underlying disease.