Dexamethasone for children to reduce fever usually lasts for 2-3 days, but there are some individual differences that need to be determined on a case-by-case basis. Dexamethasone belongs to the class of long-acting glucocorticoids and can be used for the treatment of acute inflammation and high fever in children. Since dexamethasone has a long half-life (i.e., the time it takes for the maximum concentration of the drug in the blood to decrease by half) of about 36-72 hours, the effect of reducing fever in children with high fever usually lasts for 2-3 days after injection. Although dexamethasone has a good antipyretic effect, it is not recommended to be used solely to reduce fever, as it may reduce the immunity of the body and may also lead to edema and other conditions in the child. During the illness, children need to eat a light diet, avoid spicy and stimulating, and should open the windows regularly to keep the air circulating in the room, as well as pay attention to replenishing fluids and drinking warm water appropriately.