Mesacol Suppository contains mesalamine (5-aminosalicylic acid / 5-ASA), a well-established anti-inflammatory agent used in inflammatory bowel disease (IBD). Unlike oral therapies, this suppository delivers medication directly to the rectum and sigmoid colon, ensuring high local drug concentration where inflammation is most active.

It is particularly effective in patients with ulcerative proctitis and proctosigmoiditis, where disease involvement is limited to the distal colon. Mesalamine works by reducing inflammatory mediators in the colonic mucosa, helping relieve symptoms such as rectal bleeding, urgency, and discomfort.

Mesacol is commonly used both for inducing remission during flare-ups and for maintaining remission in chronic cases. It may also be prescribed alongside oral mesalamine for broader disease control.