Vitamin AD drops are also known as a combination of vitamin A and vitamin D. Vitamin AD drops are usually given to babies until they are about 2 years old. Vitamin A and vitamin D are both important for the growth and development of babies, and generally babies should be supplemented with vitamin AD drops 1 to 2 weeks after birth until they are about 2 years old. This is because after the age of 2, the baby outdoor activities are relatively more, can receive enough light, conducive to the body of vitamin D synthesis, and this age of the baby’s diet is relatively rich, can provide sufficient nutrition for the body, therefore, usually do not need to supplement additional AD drops. It should be noted that, supplemental vitamin AD must be carried out under the guidance of a doctor, can not be taken without authorization, so as to avoid overdose caused by poisoning.