Fioricet is a brand of medicine that contains few different kinds of drugs, acetaminophen, butalbital and caffeine. It is typically used to relieve headaches, muscle pain, and other types of pain. Acetaminophen is a fever reducing agent and pain reliever. Barbiturates are a class of medications that includes butalbital. It relieves tension headaches by relaxing muscular spasms. Caffeine is a stimulant for the central nervous system, and it improves blood flow by relaxing muscular spasms in blood vessels.