Generally, children with fever after vaccination can take Merlin because it is composed of ibuprofen, which is a non-steroidal antipyretic and analgesic drug that can effectively reduce high fever in children. Children who have fever after vaccination and whose fever temperature exceeds 38.5℃ in the axilla, have poor mental status and always want to sleep, etc. can take ibuprofen to reduce fever. In this case, ibuprofen can be used to reduce the heat treatment, which can relieve the child’s discomfort. If the fever is less than 38.5℃, it is sufficient to drink warm water or apply antipyretic patches without using Merlin.