MRI equipment is noisy in normal operation, takes a long time to examine, and requires the patient to remain in a fixed position for a long time; therefore, in general, it is difficult for preschoolers or children with low intelligence to cooperate in completing the examination. To achieve the image quality necessary for diagnosis, pharmacological sedation is required. Generally, chloral hydrate is used orally or as a reserved enema. 10% chloral hydrate is the safest sedative drug for children; the oral dose is 75~100mg/kg for those weighing less than 10kg; the enema dose is 0.3~0.5mg/kg, with the maximum dose not exceeding 2g, diluted 1~2 times, and the enema is reserved via the anus 30~40min before the scan. Enema is more effective for patients under 5 years of age; patients over 5 years of age should be administered intramuscularly or intravenously. Special attention should be paid to the use of sedative drugs in pediatric patients. Contraindications include severe heart disease, hepatic and renal decompensation, respiratory and circulatory disorders, etc.; patients’ respiratory and circulatory vital signs should be closely observed after the administration of drugs; patients using sedative drugs should be left only after regaining consciousness.