The side effects of vitamin D drops are mainly vitamin D toxicity, causing hypercalcemia, manifested as dizziness, nausea, and fatigue. Contraindications are patients with hypercalcemia, hyperphosphatemia with renal rickets can not be used. Vitamin D drops are used for the treatment of vitamin D deficiency, prevention and treatment of rickets, osteochondrosis and infantile tetany. Oral vitamin D drops can not be taken in excess, there will be vitamin D poisoning, causing hypercalcemia, loss of appetite, depression, vomiting, diarrhea and even soft tissue heterotopic ossification. Contraindications to vitamin D drops are mainly related to hypercalcemia-related diseases, chronic renal failure, hypercalcemia, hyperphosphatemia with renal rickets patients, etc., are prohibited to take vitamin D drops. Vitamin D drops should be taken under the guidance of a physician, and should not be taken in large quantities over a long period of time, so as not to cause chronic vitamin D toxicity.