Aspirin (Acetylsalicylic Acid) is a COX inhibitor that inhibits COX1 and COX2 (IC50=5/210 μg/mL) with selective, irreversible, and oral activity. Aspirin is also a histone deacetylase inhibitor that up-regulates the cell cycle blocking protein, p21. Aspirin has a variety of activities. Aspirin has anti-inflammatory, antipyretic and analgesic, and antiplatelet aggregation activities.