Merlin is usually not recommended for fevers of 38°C. The main ingredient of Merlin is ibuprofen, which is a commonly used fever-reducing drug in life. For fever cases of 38℃, physical cooling, such as cold packs of ice bags and alcohol baths, is usually used first. When physical cooling is not effective, only then consider the use of antipyretic drugs. When a fever of unknown origin is encountered, antipyretic drugs are usually not used first, because the fever will cover up the patient’s symptoms and misdiagnosis. Antipyretics are usually used only when the cause of the fever is identified and treated. Indications for the use of antipyretics include a fever of 39°C or higher, or the presence of febrile convulsions. Antipyretics may also be chosen when the fever is not high, but the patient has significant headache, muscle pain, or impaired consciousness, which seriously affects the patient’s recovery from the disease, or causes abnormal cardiopulmonary function, and the patient has difficulty tolerating high fever.