(HealthDay News) — A colonoscopy allows a doctor to look inside the large intestine for early signs of cancer, ulcers and other abnormalities.

The companies day before the test, you’ll be given a preparation that will completely empty your bowel, the U.S. National Digestive Diseases Information Clearinghouse says.

You’ll also be asked to eat nothing but broth, coffee or tea, strained fruit juice (no pulp), gelatin or water.

You’ll need someone to drive you to and from the procedure, as you’ll be given a light anesthetic during the test, which takes about 30 to 60 minutes. The doctor will insert a flexible, lighted tube into your rectum and slowly guide it into your colon.

If something unusual like a polyp is spotted, your doctor may remove all or part of it to have it evaluated for signs of disease.