Antipyretic medicines are effective against fever. Aspirin is antipyretic. With a small fever, you might not need anything antipyretic, but if you fever rises much above 100, it can be very dangerous. Besides antipyretic medicine, there are antipyretic measures you can take such as holding a cold, wet rag to a patient's forehead. Since the Greek prefix anti- means "against" and pyr means "fire," it only makes sense that anything antipyretic works against the fire of a fever.