(HealthDay News) -- Colon polyps are extra tissue that form along the large intestine, also called the colon. Polyps are most often benign, but should be removed to check for cancer, the National Digestive Diseases Clearinghouse says.

Polyps occur most often in people aged 50 and older. Symptoms of colon polyps may include black or bloody stools, anal bleeding, diarrhea or constipation that lasts for more than a week.

You're more likely to get polyps of the colon -- and should be tested for them -- if you're 50 or older, if you've had some before, or if you have a family history of colon polyps or colon cancer.

If polyps are found during exploratory procedures called colonoscopies or sigmoidoscopies, the doctor should remove the excess tissue.