Fioricet is a prescription medication primarily used for the treatment of tension headaches. It is a combination drug that contains three active ingredients: butalbital, acetaminophen, and caffeine. Butalbital is a barbiturate that helps to relax muscle contractions involved in a tension headache. Acetaminophen is a pain reliever and fever reducer. Caffeine is a central nervous system stimulant that relaxes muscle contractions in blood vessels to improve blood flow.