Seeing blood when you poop is alarming, but it doesn’t always signal something serious. The most common causes are hemorrhoids and small tears in the skin around the anus, both of which typically resolve on their own. That said, blood in your stool can also point to conditions that need medical attention, so the color, amount, and any accompanying symptoms all matter when figuring out what’s going on.
What the Color of the Blood Tells You
The color of blood in your stool is a useful clue about where the bleeding originates. Bright red blood generally comes from the lower part of your digestive tract: the colon, rectum, or anus. Because it hasn’t traveled far, it stays red. You might see it on the toilet paper, dripping into the bowl, or coating the surface of your stool.
Black, tarry stools point to bleeding much higher up, typically the stomach or upper small intestine. Blood that travels the full length of your digestive system gets broken down by digestive enzymes along the way, which turns it dark and gives the stool a sticky, tar-like consistency. This type of bleeding is less obvious at first glance because it doesn’t look like blood.
Maroon-colored stool falls somewhere in between and can indicate bleeding in the middle sections of the digestive tract, like the small intestine or the right side of the colon.
The Most Common Culprits
Hemorrhoids are by far the most frequent reason people notice blood after a bowel movement. They’re swollen veins around the anus, and while they can look concerning, most don’t cause pain. You might see small amounts of bright red blood on the toilet paper or in the bowl. They tend to flare up and then settle down, often triggered by straining, sitting for long periods, or constipation.
Anal fissures are another common cause. These are small tears in the skin lining the anus, usually from passing hard or large stools. Unlike hemorrhoids, fissures tend to hurt, sometimes quite a bit, especially during and right after a bowel movement. You may also notice itching or burning that lingers. The bleeding pattern is similar to hemorrhoids: bright red blood when you poop or wipe.
The key difference between the two is pain. Hemorrhoids are usually painless or mildly uncomfortable. Fissures sting and burn. Both are treatable at home with increased fiber, plenty of water, and warm baths, though persistent cases sometimes need medical treatment.
Diverticular Bleeding
Small pouches can form in the walls of the colon over time, a condition called diverticulosis that becomes increasingly common after age 40. These pouches are usually harmless, but occasionally a blood vessel near one of them bursts. When that happens, the bleeding can be sudden, heavy, and painless. The stool is often bright red to dark maroon and may contain jelly-like clots.
Diverticular bleeding is the most common cause of significant lower digestive tract bleeding in adults, accounting for roughly 17 to 40 percent of cases. It tends to stop on its own, but the volume of blood can be frightening. Obesity roughly doubles the risk, and regular use of aspirin or common anti-inflammatory painkillers like ibuprofen is associated with these episodes. For adults over 65, this type of bleeding can be more dangerous, particularly for those already managing conditions like high blood pressure, diabetes, or kidney disease.
When Blood Signals Something More Serious
Rectal bleeding can also be a symptom of inflammatory bowel disease (conditions like Crohn’s disease or ulcerative colitis) or colorectal cancer. These are less common than hemorrhoids or fissures, but they’re the reason persistent or unexplained bleeding deserves medical evaluation.
Colorectal cancer tends to cause bleeding that is ongoing or gradually worsening, rather than the come-and-go pattern of hemorrhoids. It’s also more likely to show up alongside other changes: bowel habits that shift for no clear reason (new constipation, new diarrhea, or stools that become noticeably narrower), a feeling that your bowel isn’t fully emptying, unexplained weight loss, reduced appetite, or persistent fatigue. Any of these changes lasting more than a couple of days warrants a conversation with a doctor, especially when paired with blood in the stool. Only about 5 percent of colorectal cancer cases occur in people under 40, but the disease has been rising in younger adults in recent years.
Upper Digestive Tract Bleeding
Stomach ulcers and other problems in the upper digestive tract typically produce black, tarry stools rather than visible red blood. Some people also vomit blood, which can look bright red or resemble dark coffee grounds. If you’re seeing dark, sticky stools and haven’t recently taken iron supplements or bismuth medications (like Pepto-Bismol), that pattern points to bleeding above the small intestine.
In rare cases where upper digestive bleeding is very rapid, the blood can actually pass through quickly enough to come out bright red. This is a more urgent situation and is usually accompanied by feeling faint, lightheaded, or generally unwell.
Things That Look Like Blood but Aren’t
Before assuming the worst, consider what you’ve eaten or taken recently. Beets and foods with red food coloring can make stool appear reddish. Iron supplements, black licorice, blueberries, activated charcoal, and bismuth-containing medications can all turn stool black. These changes are harmless and resolve once you stop consuming the item in question.
What Happens at the Doctor
If you go in for rectal bleeding, expect the evaluation to be guided by how much you’re bleeding and how stable you are. For intermittent or small amounts of bright red blood, especially in younger adults, a physical exam of the lower rectum and anus is often the starting point. This is enough to identify hemorrhoids and fissures in many cases.
When the cause isn’t obvious or there are concerning symptoms, a colonoscopy is the standard next step for suspected lower digestive tract bleeding. A small camera on a flexible tube is guided through the colon, and studies show this approach identifies the bleeding source in more than 70 percent of patients. If upper digestive bleeding is suspected (black stools, vomiting blood), a similar scope is passed through the mouth to examine the esophagus, stomach, and upper small intestine.
For bleeding that originates in the small intestine, which is harder to reach, doctors may use capsule endoscopy. You swallow a tiny pill-sized camera that takes images as it passes through. This method detects small bowel problems roughly twice as often as traditional scope-based approaches.
Signs That Need Emergency Attention
Most rectal bleeding is not an emergency. A small streak on the toilet paper from a known hemorrhoid can be monitored at home. But certain combinations of symptoms signal significant blood loss that requires immediate care:
- Heavy or continuous bleeding that doesn’t slow down
- Dizziness or lightheadedness when you stand up
- Rapid, shallow breathing or a racing heart
- Cold, clammy, or pale skin
- Confusion, fainting, or blurred vision
- Severe abdominal pain or cramping alongside the bleeding
These are signs your body is struggling to compensate for blood loss. If you notice any of them, have someone drive you to an emergency room or call for help. Even without those red flags, any new or unexplained blood in your stool is worth bringing up with a doctor. The visit is usually straightforward, and most causes turn out to be manageable once identified.