Aspirin is in a class of drugs called salicylates. Aspirin works reducing substances in the body that cause pain and inflammation. It is used to reduce pain, inflammation, and fever. Caffeine is used in this combination to increase the pain relieving effects of aspirin and orphenadrine. Orphenadrine is a muscle relaxant. It works by blocking nerve impulses (or pain sensations) that are sent to the brain. Aspirin/caffeine/orphenadrine is used, along with rest and physical therapy, to treat injuries and other painful muscular conditions. Aspirin/caffeine/orphenadrine may also be used for purposes other than those listed in this medication guide.