Zocdoc Answers

Medical questions & health advice by board certified doctors

"What causes blood to appear in stool?"


I'm a middle aged man and for a few weeks (on and off) I've found blood in my stool. What causes this? I've tried researching it myself, but it seems like there are so many possibilities, I'm just shooting in the dark. Should I just see a doctor?


First off, YES you should go see a doctor. There are many different reasons to have blood in the stool and a full evaluation by a physician is necessary to determine the cause of the bleeding and any further evaluation and treatment. That being said, there are a few likely conditions that cause bright red blood in the stool: -hemorrhoids: A hemorrhoid is simply a dilated rectoanal blood vessel.

See a doctor who can help

Find a Primary care-doctors near you

these vessels are very friable and tend to bleed with defecation, especially with the passage of hard stool. -diverticulosis: Diverticuli are small outpouchings of the colon that tend to involute colonic blood vessels and cause painless bleeding per rectum. -vascular malformations in the colon or small intestine -colon cancer: this is obviously a concerning possibility and all the more reason for you to have a full evaluation of your symptoms with your doctor. one of the ways to detect colon cancer is through a procedure known as a colonoscopy in which a small camera is passed through the anus into the colon and the interior wall of the colon is inspected for masses or polyps. It is recommended that all adults have a colonoscopy at least every ten years starting at age 50. Hope this helps!

Zocdoc Answers is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Medical professionals who provide responses to health-related questions are intended third party beneficiaries with certain rights under Zocdoc’s Terms of Service.