5 acetylsalicylic acid

5-Acetylsalicylic acid (5-acetyl-2-hydroxybenzoic acid) has anti-inflammatory effects and can be used to treat inflammatory bowel disease, including ulcerative colitis, inflamed anus or rectum, and to maintain remission in Crohn's disease.

Aspirin is an orally active, selective, and irreversible inhibitor of COX-1 and COX-2 with IC₅₀ values of 5 and 210 μg/mL, respectively. It induces apoptosis, inhibits NF-κB activation and platelet prostaglandin synthesis, thereby preventing thrombosis. Additionally, it acts as a histone deacetylase inhibitor that upregulates p21, exhibiting anti-inflammatory, antipyretic, analgesic, and anti-platelet aggregation activities. Aspirin is commonly used to induce gastric ulcer models.