There is no study to confirm what medication is used to reduce fever quickly. Fever reduction is only a temporary relief of symptoms, you can use physical cooling, ibuprofen and other drugs, but you need to identify the cause of fever and actively treat the cause, the common causes of upper respiratory tract infections, hyperthyroidism and so on. 1. Upper respiratory tract infection: fever, sneezing, runny nose, nasal congestion and other symptoms may occur after the body is infected by bacteria or viruses. Physical hypothermia can be used to reduce fever below 38.5°, and ibuprofen can be used to reduce fever above 38.5°. At the same time, oral antibiotic amoxicillin or antiviral drug oseltamivir should be taken to treat bacterial or viral infections. 2. Hyperthyroidism: The thyroid gland secretes too much thyroid hormone, which will show symptoms such as palpitations, excessive eating, easy to get hungry and fever. It is necessary to check the five items of thyroid function to make a clear diagnosis. Fever caused by hyperthyroidism can be inhibited by oral administration of methimazole or propylthiouracil to inhibit excessive thyroid hormone production. It is recommended to consult a doctor in a timely manner, under the guidance of the doctor to standardize the use of medication, to avoid blindly taking medication on their own.