My colonscopy shows that i have sessile polyp ( neck less ) in my rectum and rectal ulcer am on pentasa (mesalamine) what to do else ?

Talk to your doctor: If you are on Pentasa (mesalamine) because your doctor thinks you have ulcerative colitis then this is the expected finding. The ulcers leave areas of normal lining that look like ulcers because of the surrounding ulcers. These are called pseudopolyps. Biopsies are often needed to tell for sure. If the ulcers are large and extensive you may need to add another medication.

Aspirin: There are some studies suggesting that low dose Aspirin may prevent polyps. Also if your colonoscopy was at thirty then any siblings and your children will need a colonoscopy at 20.