Used primarily in the treatment of ulcerative colitis, a form of inflammatory bowel disease. It works by reducing inflammation in the colon, helping to relieve symptoms such as diarrhea, rectal bleeding, and abdominal pain. The medication is designed to release its active component, mesalamine, specifically in the large intestine, where it exerts its anti-inflammatory effect. This targeted delivery minimizes systemic absorption and reduces the risk of side effects. Olsalazine sodium is typically prescribed for patients who are intolerant to sulfasalazine, offering an alternative with a similar mechanism but without the sulfa component. It helps maintain remission and improve quality of life in chronic cases.