One morning after having a bowel movement I found bright red blood in the toilet and worried if that meant I had cancer. I visited my doctor for a general checkup and mentioned the problem.
He asked me if my family had a history of bowel cancer or if I was experiencing abdominal pain. I could answer both questions in the negative.
He then suggested that I get a colonoscopy just to be sure of the cause of the bleeding. While many people joke about how horrible this procedure can be, I thought the worst part of it was taking the medicine the night before that would completely empty my bowels. This is totally necessary, though, so that the scope that they use can take clear pictures of any abnormalities that may be found.
I was put under anesthetic for the procedure itself. The results: I had internal and external hemorrhoids and a diverticulum (a sac or pouch that branches out from the intestine) any of which could have bled when I voided. None indicate cancer now or in the future. In fact, the technician said, "See you in ten years for your next colonoscopy!"
After the colonoscopy, I was directed to limit physical activity for a day or so. A colonoscopy is considered a surgical procedure and the limitations afterwards are to allow the colon to heal.
Since my colonoscopy, I have done further research about the causes of rectal bleeding. The blood I discovered was bright red, but had it been dark red there would have been greater cause for concern because the blood would have come from a place deeper in the intestinal tract. According to Dr. Gregor Brown in the June 2004 issue of Medicine Today, bright red bleeding that is not observed after every bowel movement is mostly caused by either hemorrhoids or an anal fissure (where the anal lining has been lacerated due to constipation and straining). If hemorrhoids or anal fissures are the cause of bleeding, something that will soften the stools and prevent constipation may be recommended so that there is no further tearing or irritation. Hydrocortisone suppositories or medicated wipes can also ease the discomfort.
More serious but less likely causes of rectal bleeding include large polyps, Crohn's disease, cancer, and inflammatory bowel disease. During the colonoscopy, abnormal tissues including polyps will be removed and sent to the lab to be examined for cancerous cells.
Bleeding accompanied by diarrhea may indicate infectious colitis or inflammatory bowel disease and should be treated as soon as possible.
My advice is to see your doctor with a written log detailing your observations (how often, how much blood, what color the blood is, whether or not the blood is mixed in with the stool or is found on the toilet paper, if pain accompanies bowel movements, etc.) and express your concerns.
For your own peace of mind, get any rectal bleeding checked.