Vitamin D and vitamin AD, are generally not recommended for infants to take together. It may lead to excessive intake of vitamin D and accumulation of vitamin D in the infant’s body, which is not conducive to normal growth and development. Vitamin AD is mainly composed of vitamin A and vitamin D. Taking vitamin D at the same time will lead to the intake of vitamin D far exceeding the body’s needs, and it is easy to accumulate vitamin D in the body, interfering with the normal development and physiological function of the bones, muscles, and the nervous system, which will have an adverse effect on the healthy growth of infants. The correct way to take vitamin D and vitamin AD is to take them every other day, and the specific dosage should be consulted in detail with the doctor and decided according to the specific situation of the baby, to ensure the safety of the baby’s taking. If there is any discomfort, prompt medical attention is recommended.