The active ingredient in aspirin is acetylsalicylic acid. This compound is widely recognized for its analgesic, anti-inflammatory, and antipyretic properties. Aspirin is commonly used to relieve mild to moderate pain, reduce inflammation, and lower fever. Additionally, it is often utilized in low doses for its anticoagulant effects to mitigate the risk of heart attacks and strokes by preventing blood clots. First synthesized in the late 19th century, acetylsalicylic acid remains a staple in medicine for both acute and preventive treatment of various conditions, contributing to its status as one of the most commonly used medications globally.