Seeing blood in the toilet or on the paper is frightening, and it is one of the most common reasons people call a gastroenterologist. Most of the time the cause is something minor, like hemorrhoids. But blood in the stool can also be the first sign of a problem that needs treatment, so it should never be ignored. The color of the blood gives useful clues about where it is coming from. Here is how to read those clues and when to get checked.
What the Color Tells You
- Bright red blood usually comes from the lower colon, rectum, or anus. Common sources are hemorrhoids and small tears called fissures.
- Dark red or maroon blood often points to bleeding higher up in the colon or small intestine.
- Black, tarry stool suggests bleeding in the stomach or upper digestive tract, where blood has been partly digested. This needs prompt attention.
Common Causes
Blood in the stool can come from many sources, including:
- Hemorrhoids: swollen veins near the anus and the most common cause of bright red blood. Learn more in our hemorrhoid guide.
- Anal fissures: small tears in the lining of the anus, often after hard stools.
- Diverticulosis: small pouches in the colon that can bleed.
- Polyps: growths in the colon that can bleed and may turn into cancer over time.
- Inflammatory bowel disease: conditions like ulcerative colitis and Crohn's disease.
- Ulcers and other problems in the stomach or upper tract.
- Colorectal cancer: less common, but an important reason not to assume the cause is harmless.
When It Is an Emergency
Get medical care right away if you have heavy bleeding, black or tarry stools, blood with dizziness or weakness, a fast heartbeat, or severe belly pain. These can point to significant bleeding that needs urgent treatment.
How We Find the Cause
The most useful test is a colonoscopy, which lets me look at the entire colon, find the source of bleeding, remove polyps, and take samples if needed. When the color or symptoms suggest the upper tract, an upper endoscopy may be done instead. Blood tests help check for anemia from ongoing blood loss.
Do Not Assume It Is Just Hemorrhoids
Even if you have had hemorrhoids before, new or different bleeding should be checked. Hemorrhoids and colorectal cancer can cause similar-looking bleeding, and the only way to be sure is an exam. This is especially important if you are over 45, have a family history of colon cancer, or have other symptoms like a change in bowel habits or weight loss.
When to See a Gastroenterologist
Make an appointment if you notice blood more than once, if it comes with a change in your bowel habits, or if you have any of the warning signs above. Finding the cause early gives you the best outcome, and in the case of polyps, removing them can prevent cancer before it ever starts.
Talk to a Gastroenterologist in Mountainside, NJ
If your symptoms keep coming back or you are not sure what is causing them, Dr. Amber Khan can help. We see patients from across Union County and New Jersey.