Aspirin is a type of pain-relieving pill that has been used for centuries to treat a variety of ailments. It is an over-the-counter medication that works by blocking the production of certain chemicals in the body that cause inflammation and pain. Aspirin is most commonly used to treat headaches, muscle aches, and arthritis, but it can also be used to reduce fever and prevent heart attacks and strokes. Aspirin is one of the most widely used pain-relieving pills available and is considered safe when taken as directed.