Mesacol 400 mg contains Mesalamine (also known as 5-Aminosalicylic acid), which is an anti-inflammatory drug used to treat inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn’s disease. It works by reducing inflammation in the lining of the colon, thereby helping to control symptoms like diarrhea, rectal bleeding, and abdominal pain. Mesacol is typically used for both the treatment of active disease and for maintaining remission. It is usually taken orally in the form of delayed-release tablets, allowing the medicine to be released in the colon where it is most needed. The dosage and duration are determined by the severity of the condition and the response to treatment, under a doctor’s supervision.