Bleeding after a bowel movement is common, and the most likely cause is hemorrhoids or a small tear in the skin around the anus. These two conditions account for the vast majority of cases, especially when the blood is bright red and shows up on toilet paper or in the bowl. That said, rectal bleeding can sometimes signal something more serious, so the color of the blood, the amount, and any symptoms that come with it all matter.
Hemorrhoids: The Most Common Cause
Hemorrhoids are swollen blood vessels in or around the anus. They’re extremely common, and they’re the single most frequent reason people see bright red blood after wiping. Internal hemorrhoids sit inside the rectum where there are few pain-sensing nerves, so they typically bleed without hurting. You might notice small streaks of bright red blood on the toilet paper or drops in the bowl, but feel nothing unusual.
External hemorrhoids form under the skin around the opening of the anus. These are more likely to cause pain, itching, or a noticeable lump along with bleeding. Straining during bowel movements, sitting on the toilet for long periods, chronic constipation, and pregnancy all increase your risk. Most hemorrhoids improve on their own within a few days to a couple of weeks, especially with dietary changes.
Anal Fissures: Bleeding With Sharp Pain
If the bleeding comes with a sharp, tearing, or burning pain right as you pass stool, an anal fissure is the likely culprit. A fissure is a small tear in the lining of the anus, usually caused by passing a hard or large stool. The blood is fresh and red, and the pain can last anywhere from a few minutes to several hours after you finish. Some people feel it radiating into their buttocks, upper thighs, or lower back.
Fissures are common and heal on their own in most cases, particularly if you soften your stools by eating more fiber and drinking enough water. Warm baths can also help relax the muscles around the area and speed healing.
What the Color of the Blood Tells You
Bright red blood generally means the source of bleeding is in the lower part of your digestive tract: the rectum, anus, or lower colon. This is what you’ll see with hemorrhoids, fissures, and other conditions close to the exit point. It’s the most common type and, in most cases, the least worrisome.
Dark red or maroon blood suggests the bleeding is coming from higher up in the colon. Black, tarry stools are a different situation entirely. Blood turns black as it travels through the digestive tract and gets broken down by digestive enzymes. Black stools typically point to bleeding in the stomach or small intestine, which is a more urgent concern. If your stools look black and sticky, that warrants prompt medical attention.
Less Common but Serious Causes
Inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis, can cause rectal bleeding that comes and goes over weeks or months. IBD bleeding is usually accompanied by other symptoms: persistent diarrhea, abdominal cramping, unintended weight loss, fatigue, or joint pain. Some people also develop mouth sores, skin rashes, or eye irritation. If your bleeding happens alongside several of these symptoms, your doctor will likely want to investigate further, often starting with blood work and potentially a colonoscopy.
Colorectal polyps and colorectal cancer can also cause bleeding, though they’re far less common than hemorrhoids, especially in younger adults. Nearly 94% of new colorectal cancer cases occur in adults 45 and older. The U.S. Preventive Services Task Force recommends screening starting at age 45 for average-risk adults, or earlier if you have a family history, obesity, long-term smoking, or heavy alcohol use. Black adults and American Indian and Alaska Native adults face higher incidence rates and may benefit from earlier conversations about screening. Bleeding from polyps or cancer is often subtle enough that you can’t see it without a lab test.
How Doctors Find the Source
If your bleeding doesn’t resolve on its own or keeps coming back, a doctor will typically start with a physical exam that includes checking the rectum with a gloved finger for hemorrhoids or other issues. From there, the next step depends on your age, symptoms, and risk factors. An anoscopy or proctoscopy uses a short, lighted tube to look at the anus and lower rectum. A flexible sigmoidoscopy examines the lower colon. A colonoscopy examines the entire colon and is the standard screening tool for polyps and cancer.
Your doctor may also order a fecal occult blood test, which detects hidden blood in your stool that isn’t visible to the naked eye. If the suspected source is higher up in the digestive tract, an upper endoscopy can look at the stomach and small intestine.
Preventing Bleeding From Straining
Since hemorrhoids and fissures are overwhelmingly the top causes of post-bowel-movement bleeding, the most effective prevention strategy is making stools easier to pass. Federal dietary guidelines recommend 14 grams of fiber per 1,000 calories you eat, which works out to about 28 grams per day on a standard 2,000-calorie diet. Most people fall well short of that number. Good sources include beans, lentils, whole grains, berries, broccoli, and pears.
Increase fiber gradually over a week or two rather than all at once, or you’ll likely deal with bloating and gas. Drinking enough water matters just as much, because fiber absorbs liquid to soften stool. Without adequate hydration, extra fiber can actually make constipation worse. Beyond diet, avoid sitting on the toilet longer than necessary (put the phone down), and don’t strain or hold your breath to force a bowel movement. If you feel the urge to go, don’t delay it, as waiting can lead to harder stools.
Signs That Need Immediate Attention
Most rectal bleeding is not an emergency, but certain combinations of symptoms require urgent care. Seek emergency help if you experience heavy or continuous bleeding alongside any of the following: dizziness or lightheadedness when you stand up, rapid or shallow breathing, fainting, confusion, blurred vision, nausea, cold or clammy skin, or very little urine output. These are signs your body may be losing enough blood to affect circulation.
You should also get to an emergency room if rectal bleeding comes with severe abdominal pain or cramping that doesn’t let up, a fever above 100.3°F with chills, or blood clots in your stool. These patterns can indicate infections, a severely inflamed colon, or other conditions that need treatment right away.