Antipyretics (/ænti.paɪˈrɛ.tɪks/), from the Greek anti, against, and pyreticus, pertaining to fever, are substances that reduce fever.

Antipyretics cause the hypothalamus to override an interleukin-induced increase in temperature. The body then works to lower the temperature, resulting in a reduction in fever.

Most antipyretic medications have other purposes. The most common antipyretics in the United States are ibuprofen and aspirin, which are used primarily as pain relievers. Non-steroidal anti-inflammatory drugs (NSAIDs) are antipyretic, anti-inflammatory, and pain relievers.

There is some debate over the appropriate use of such medications, as fever is part of the body's immune response to infection.

A study published by the Royal Society claims fever suppression causes at least 1% more influenza cases of death, resulting in at least 700 extra deaths per year in the United States alone.