Bleeding from your butt is surprisingly common, affecting roughly 15% of adults in any given year. The most frequent cause, by a wide margin, is hemorrhoids, which are swollen veins in or around the rectum. While that’s reassuring for most people, rectal bleeding can also signal other conditions ranging from minor tears to more serious problems like inflammatory bowel disease or colon polyps. The color of the blood, whether it hurts, and how much you’re losing all help narrow down what’s going on.
What the Color of Blood Tells You
The color of the blood you see is one of the most useful clues about where the bleeding is coming from. Bright red blood on the toilet paper or in the bowl typically means the source is near the exit: the rectum or anus. This is the pattern you’d see with hemorrhoids, anal fissures, or bleeding from the lower colon.
Dark red or maroon-colored blood suggests the bleeding originates higher up in the colon. Diverticular bleeding from the right side of the colon, for instance, often appears dark or maroon rather than bright red. Black, tarry stools point to bleeding even further upstream, usually the stomach or upper intestine, where blood has been partially digested on its way through your system. If you notice black or tarry stools, that warrants prompt medical attention since the source is harder to identify on your own.
Hemorrhoids: The Most Common Cause
Hemorrhoids are the number one reason adults see blood after a bowel movement. They’re essentially swollen blood vessels inside the rectum (internal hemorrhoids) or around the outside of the anus (external hemorrhoids). Internal hemorrhoids often bleed painlessly. You might notice bright red blood on the toilet paper or dripping into the bowl, with no discomfort at all. External hemorrhoids can cause itching or mild soreness, but pain isn’t always part of the picture.
Straining during bowel movements, sitting for long periods, pregnancy, and chronic constipation all increase your risk. Most hemorrhoids improve on their own within a few days to a couple of weeks, especially if you soften your stool by eating more fiber and drinking more water.
Anal Fissures: When It Hurts to Go
If the bleeding comes with a sharp, stinging pain during or after a bowel movement, an anal fissure is a likely culprit. A fissure is a small tear in the lining of the anal canal, usually caused by passing a hard or large stool. The pain can be intense enough that people start avoiding the bathroom, which only makes constipation worse and slows healing.
Most fissures heal within a few weeks with basic home care. Soaking in warm water for 10 to 20 minutes several times a day, particularly after bowel movements, helps relax the muscles around the anus and promotes healing. Keeping stools soft through extra fiber and fluids is equally important. If a fissure doesn’t improve after a few weeks, a doctor can offer additional options.
Diverticular Bleeding
Small pouches can form in the wall of the colon over time, especially in people over 40. These pouches are called diverticula, and they’re extremely common. Most cause no trouble, but when a blood vessel near one of these pouches breaks, the result is painless but often heavy bleeding. Diverticular bleeding accounts for 30 to 50 percent of large-volume rectal bleeding cases, making it the most common cause of sudden, significant blood loss from the lower digestive tract.
The hallmark is passing a noticeable amount of blood with little or no abdominal pain. Some people feel cramping or an urgent need to have a bowel movement, and dizziness or weakness can follow if the blood loss is substantial. Most diverticular bleeds stop on their own, but the volume of blood can be alarming enough to send people to the emergency room, which is reasonable.
Inflammatory Bowel Disease
Ulcerative colitis and Crohn’s disease both cause chronic inflammation in the digestive tract, and bloody stools are one of the hallmark symptoms. Unlike hemorrhoids or fissures, IBD usually comes with additional signs: persistent diarrhea, abdominal cramping, fatigue, and unintentional weight loss. The bleeding tends to be ongoing or recurring rather than a one-time event.
If you’re seeing blood in your stool alongside changes in bowel habits that last more than a couple of weeks, particularly if you’re also losing weight or feeling unusually tired, that pattern points toward something beyond a surface-level cause and is worth investigating.
Colon Polyps and Colorectal Cancer
This is the possibility that worries most people, and while it’s far less common than hemorrhoids, it’s the reason rectal bleeding shouldn’t be dismissed indefinitely. Colon polyps are small growths on the inner lining of the colon. Most are harmless, but some can develop into cancer over time. Both polyps and colorectal cancer can cause blood in the stool, often without any pain.
The U.S. Preventive Services Task Force recommends colorectal cancer screening starting at age 45 for people at average risk. If you have a family history of colorectal cancer or inflammatory bowel disease, screening may need to start earlier. Catching polyps before they become cancerous is one of the most effective forms of cancer prevention available.
Medications That Increase Bleeding Risk
Certain medications can cause or worsen bleeding anywhere in the digestive tract. Anti-inflammatory painkillers like ibuprofen and naproxen are among the most common culprits. Blood thinners, low-dose aspirin, and corticosteroids also raise the risk. Combining these drugs amplifies the danger significantly. Taking a standard anti-inflammatory painkiller alongside a corticosteroid, for example, increases the risk of upper digestive bleeding nearly 13-fold compared to taking neither. Even certain antidepressants (SSRIs) can increase bleeding risk when combined with anti-inflammatory drugs.
If you’re on any of these medications and notice new or worsening rectal bleeding, that’s worth mentioning to whoever prescribed them. The bleeding may not be from a new condition at all, but from how your medications interact.
What to Expect at the Doctor
If you go in for rectal bleeding, the evaluation typically starts with a physical exam and questions about your symptoms, diet, medications, and family history. Depending on what the doctor suspects, they may use a small tube called an anoscope to look at the anus and check for hemorrhoids. A sigmoidoscopy examines the rectum and lower colon using a flexible lighted tube. A colonoscopy goes further, checking the entire colon with a camera, and is the standard test when there’s concern about polyps, cancer, or inflammatory bowel disease.
Which test you get depends on your age, symptoms, and risk factors. A 25-year-old with bright red blood on the toilet paper and a history of constipation will likely get a different workup than a 55-year-old with dark blood mixed into the stool.
Signs That Need Urgent Attention
Most rectal bleeding is not an emergency, but certain combinations of symptoms mean you should get help quickly. Heavy bleeding that doesn’t slow down, blood that’s dark or mixed into your stool, dizziness, rapid or shallow breathing, nausea, confusion, or fainting all suggest significant blood loss. If you feel lightheaded when you stand up after a bleeding episode, your body is telling you it’s lost enough blood to affect circulation. That’s a situation for the emergency room, not a wait-and-see approach.