Her articles have appeared in such publications as “The Washington Post,” “Reuters Health Information” and “Discover,” as well as various trade journals. Bryant holds a Bachelor of Arts in political science from the University of Pennsylvania. Photo Credit barfuss am strand image by Heiner Witthake from Fotolia.com Polyps are growths that can occur on the inside of the colon (bowel) or rectum. Although most are benign, they can turn into colon or rectal cancer if left untreated. You’re more risk of developing polyps if you’re older than 50, have a family history of polyps or have someone in your family who has had colon or rectal cancer. Because people with polyps often have no symptoms, polyps are often only detected during a routine colonoscopy, a medical procedure that allows a doctor to view the inner walls of your large intestine. If a polyp is found, it should be removed and tested in a laboratory to make sure it’s not cancerous. Bloody Stools According to the Penn State Hershey Medical Center, the top symptom of polyps is bleeding during bowel movements. Blood may appear as red streaks in the bowel itself, in the toilet water or on a toilet wipe. It can also make the bowel look black. Often, though, the blood is not clearly visible in the stool.