Patients with familial adenomatous polyposis. Celecoxib is used to decrease growths found in the intestines of persons with a family history of this condition. If you experience flatulence or diarrhea dizziness headache or insomnia. The risk of serious effects on the stomach or intestines, including bleeding or perforation. Celecoxib differs from other anti-inflammatory drugs in that it causes less inflammation and ulceration of the stomach and intestine and does not interfere with the function of the blood platelets and, as a result, does not reduce clotting and lead to increased bleeding like other NSAIDs.