Sulfasalazine is a medication primarily used to treat inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease, as well as rheumatoid arthritis. It works by reducing inflammation in the intestines and joints, helping to alleviate symptoms like pain and swelling. This drug is a combination of sulfapyridine and 5-aminosalicylic acid (5-ASA). It is usually taken orally in tablet form and may take several weeks to show its full effects. Common side effects can include nausea, headache, and rash, but serious side effects are rare.