Aspirin is the common name for acetylsalicylic acid, which is used as a non-steroidal anti-inflammatory drug (NSAID) to relieve pain, reduce fever, and minimize swelling. It is also used as an anti-platelet drug to prevent blood clots and as a preventative measure for heart conditions. Aspirin is available over the counter and commonly used for headaches, colds, flu, and preventative heart care, though it can have gastrointestinal side effects.