Bleeding when you poop is common and usually caused by something minor, like hemorrhoids or a small tear in the skin around your anus. But the color of the blood, the amount, and any symptoms that come with it can point to very different causes, some of which need medical attention. Understanding what to look for helps you figure out whether this is a wait-and-see situation or something to bring up with a doctor soon.
What the Color of the Blood Tells You
The single most useful clue is the color of the blood. Bright red blood on the toilet paper, on the surface of your stool, or dripping into the bowl almost always means the bleeding is coming from somewhere near the exit: your rectum or anus. This is called lower GI bleeding, and the most frequent culprits are hemorrhoids and anal fissures.
Dark red or maroon-colored blood mixed into the stool suggests the bleeding is happening higher up in the colon. This can occur with conditions like diverticular disease or colon polyps. Black, tarry, sticky stool with a strong odor typically signals bleeding even further upstream, in the stomach or upper small intestine. Blood that travels that far through the digestive tract gets broken down by stomach acid, which turns it dark. If your stool looks like this, it’s worth getting evaluated promptly.
One caveat: certain foods and supplements can change stool color. Iron supplements, bismuth (the active ingredient in some stomach remedies), beets, and dark berries can all produce stools that look alarming but are completely harmless.
Hemorrhoids: The Most Likely Explanation
Hemorrhoids are swollen veins around the anus, and they’re the most common reason people see blood when they poop. You might notice bright red blood on the toilet paper or in the bowl, sometimes with itching or a noticeable lump near your anus. Most hemorrhoids don’t actually cause pain, which surprises a lot of people. The bleeding tends to happen during or right after a bowel movement, especially if you’re straining.
Hemorrhoids develop from increased pressure on the veins in that area. Chronic constipation, sitting on the toilet for long stretches, pregnancy, heavy lifting, and obesity all raise your risk. They’re extremely common and often come and go on their own. Warm baths, over-the-counter creams, and softer stools (more on that below) resolve most flare-ups within a week or two.
Anal Fissures: When It Hurts Too
If the bleeding comes with a sharp, stinging pain during bowel movements, an anal fissure is more likely than a hemorrhoid. Fissures are small tears in the skin lining the anus, usually caused by passing hard or large stools. The pain can linger as a burning or itching sensation well after you’ve finished. You may also notice bright red blood on the toilet paper or on the surface of the stool.
Fissures are more likely to cause pain than hemorrhoids because the torn skin exposes nerve endings and is vulnerable to irritation and infection. Most heal on their own within a few weeks if you can keep your stools soft and avoid straining. Persistent fissures that don’t heal sometimes need a prescription ointment or, rarely, a minor procedure.
Diverticular Bleeding
Diverticulosis, a condition where small pouches form in the wall of the colon, becomes increasingly common with age. About 30% of people over 50 have it, rising to 75% of people over 80. Most never know because it rarely causes symptoms. But roughly 10% of people with diverticulosis experience bleeding at some point, which happens when hard stool passing through a pouch stretches or erodes a blood vessel until it breaks.
Diverticular bleeding is typically painless and sudden. You may see a noticeable amount of fresh red or dark red blood in the toilet. It usually stops on its own, but the volume can be startling enough to warrant a call to your doctor. If it’s heavy or doesn’t let up, it needs emergency attention.
Colon Polyps and Colorectal Cancer
Polyps are small growths on the inner lining of the colon. Most are harmless, but some can develop into cancer over time if left in place for years. Here’s the tricky part: most colon polyps and even many colorectal cancers cause no symptoms at all. When polyps do bleed, the blood loss is often so slow and small that you can’t see it with the naked eye. Over time, this hidden bleeding can lead to iron deficiency and fatigue before you ever notice blood in the toilet.
This is exactly why routine screening matters even when you feel fine. The U.S. Preventive Services Task Force recommends that all adults begin colorectal cancer screening at age 45 and continue through age 75. Screening catches polyps before they become cancerous and detects cancers early when they’re most treatable. If you have a family history of colorectal cancer, your doctor may recommend starting even earlier.
Other Possible Causes
Inflammatory bowel diseases like Crohn’s disease and ulcerative colitis can cause rectal bleeding along with diarrhea, abdominal cramping, and weight loss. These are chronic conditions that involve inflammation in the digestive tract, and bleeding is typically one of several ongoing symptoms rather than an isolated event.
Infections from bacteria, viruses, or parasites can also irritate the lining of the intestines enough to cause bloody diarrhea. This is more common after travel, contaminated food, or a course of antibiotics that disrupted your normal gut bacteria. These infections usually resolve with treatment or on their own, but bloody diarrhea that lasts more than a couple of days deserves a medical evaluation.
How to Prevent Straining-Related Bleeding
Since hemorrhoids and fissures are by far the most common causes, preventing them comes down to keeping your stools soft and easy to pass. Dietary fiber is the most effective tool. Current guidelines recommend about 14 grams of fiber for every 1,000 calories you eat daily, which works out to roughly 25 to 35 grams for most adults. Good sources include beans, lentils, whole grains, berries, broccoli, and pears.
Increase fiber gradually rather than all at once, and drink plenty of water alongside it. Fiber without enough fluid can actually make constipation worse. Staying physically active also helps keep things moving. On the toilet, avoid sitting and scrolling for extended periods. If you feel the urge to go, don’t put it off, as waiting can harden the stool and make straining more likely.
Signs That Need Immediate Attention
A small amount of bright red blood on the toilet paper after a hard bowel movement, especially if it happens once or twice and stops, is rarely an emergency. But certain combinations of symptoms signal something more serious. Seek emergency care if rectal bleeding is continuous or heavy, or if it’s accompanied by severe abdominal pain or cramping.
Call 911 if you notice signs of significant blood loss alongside the bleeding:
- Dizziness or lightheadedness when you stand up
- Rapid, shallow breathing
- Fainting or confusion
- Cold, clammy, or pale skin
- Blurred vision
- Very low urine output
Even without those dramatic signs, bleeding that keeps recurring over several weeks, a change in your bowel habits that persists, unexplained weight loss, or black tarry stools are all worth bringing to a doctor’s attention sooner rather than later.
What to Expect at the Doctor’s Office
Your doctor will likely start with questions about the color and amount of blood, how often it’s happening, whether you have pain, and what your bowel habits look like. A physical exam usually includes a quick check of the area around and just inside the rectum, which can identify hemorrhoids and fissures right away.
Depending on what they find, they may recommend further testing. An anoscopy or proctoscopy lets the doctor look more closely at the anus and lower rectum. A flexible sigmoidoscopy examines the lower portion of the colon. A colonoscopy provides a view of the entire colon and is the gold standard for ruling out polyps, cancer, and inflammatory bowel disease. A fecal occult blood test can detect microscopic amounts of blood in a stool sample, which is useful for screening even when nothing is visible to the eye.
Before your visit, take note of the blood’s color, roughly how much there is, whether it’s on the surface of the stool or mixed in, and any other symptoms you’ve noticed. These details help your doctor narrow things down quickly.