Icosin AD, or vitamin AD drops, can be taken by newborns up to three months of age, and should be used as prescribed by a doctor. Vitamin AD drops are recommended to be started 2 weeks after birth for full-term newborns, and 1 week after birth for preterm or low birth weight newborns. Supplementation is generally recommended until about 2 years of age. Vitamin AD drops are used to prevent or treat vitamin A and vitamin D deficiencies such as rickets, pediatric tetany, and night blindness. Long-term overdose of this product can cause chronic toxicity manifesting symptoms such as bone and joint swelling, pain, dry and cracked lips, itchy skin, headache, fever, constipation, vomiting, diarrhea, nausea and so on. Hypercalcemia, chronic renal failure, renal rickets with hyperphosphatemia is prohibited. Vitamin AD should be used reasonably under the guidance of a doctor to avoid overdose or wrong use.