Blood in your stool is almost always worth paying attention to, but it’s not always an emergency. The most common causes are hemorrhoids and small tears in the skin around the anus, both of which typically heal on their own. That said, the color of the blood, how much there is, and whether you have other symptoms all help determine how urgently you need to act.
When to Go to the ER
Some situations call for immediate action. Call 911 or get to an emergency room if you’re bleeding heavily and experience any of these signs of shock: dizziness or lightheadedness when you stand up, rapid shallow breathing, blurred vision, fainting, confusion, nausea, cold or clammy skin, or very low urine output. These signs mean your body may be losing blood faster than it can compensate.
You should also have someone drive you to an ER if the bleeding is continuous or heavy, or if it comes with severe abdominal pain or cramping. Don’t wait for a scheduled appointment in these cases.
What the Color of the Blood Tells You
The shade of blood you see gives a rough clue about where the bleeding is happening inside your body. Bright red blood usually means the source is low in the digestive tract: the colon, rectum, or anus. This is the most common type, and it’s often from something minor like a hemorrhoid or a small skin tear.
Dark red or maroon blood suggests the bleeding is higher up, possibly in the upper colon or small intestine. Black, tarry-looking stool points to bleeding even further up, often in the stomach, such as from an ulcer. Blood from higher in the digestive tract takes longer to travel through your body, and digestive chemicals gradually darken it along the way. Darker blood doesn’t necessarily mean the bleeding has stopped. It just means the source is farther from the exit.
Foods and Medications That Mimic Blood
Before you panic, consider what you’ve eaten or taken recently. Beets and foods with red coloring can make stool look reddish. Iron supplements, black licorice, blueberries, activated charcoal, and bismuth-based medications like Pepto-Bismol can all turn stool black. If you’ve consumed any of these in the past day or two, that may explain what you’re seeing. The easiest way to tell: stop consuming the suspect food or supplement and see if the color returns to normal within a day or two.
The Two Most Common Causes
Hemorrhoids and anal fissures account for the vast majority of bright red rectal bleeding, especially in younger adults.
Hemorrhoids are swollen veins around the anus. You might notice bright red blood on the toilet paper or in the bowl, along with itching or mild discomfort. You may feel or see small lumps near the opening. Most hemorrhoids don’t actually cause much pain.
Anal fissures are tiny tears in the skin of the anus, usually caused by passing a large or hard stool. These are more likely to hurt, particularly during a bowel movement. You might also notice a burning or itching sensation that lingers afterward. The good news: up to 87% of anal fissures heal with simple conservative care. That means warm sitz baths (sitting in a few inches of warm water for 10 to 15 minutes), drinking more fluids, eating more fiber, and using over-the-counter stool softeners. The goal is to keep stools soft so the tear can heal without being re-injured. For fissures that don’t respond to these measures, prescription ointments that relax the muscle around the anus heal 65 to 95% of remaining cases.
Signs That Point to Something More Serious
Blood in the stool 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, but they’re the reason you shouldn’t ignore persistent bleeding.
Pay close attention if rectal bleeding comes with any of these: ongoing abdominal pain, a noticeable change in your bowel habits (new constipation, diarrhea, or narrower stools that persist for weeks), unexplained fatigue, or unintentional weight loss. The combination of bleeding plus any of these symptoms warrants a prompt visit to your doctor. Don’t delay out of embarrassment. Colorectal cancer caught early is far more treatable than colorectal cancer caught late.
What Your Doctor Will Do
If you see a doctor for rectal bleeding, the evaluation is usually straightforward. It often starts with a physical exam that includes a digital rectal exam, where the doctor uses a gloved finger to check for hemorrhoids, fissures, or anything unusual. Depending on your age, symptoms, and risk factors, they may recommend a closer look with a scope. A colonoscopy uses a thin, flexible tube with a camera to examine the entire colon. A sigmoidoscopy is a shorter version that examines only the lower portion. These procedures can both find and sometimes treat the source of bleeding in a single session.
For harder-to-find bleeding sources, imaging tests like a bleeding scan or angiography can pinpoint where blood is coming from.
Colorectal Cancer Screening by Age
Routine colorectal cancer screening is now recommended starting at age 45 for everyone at average risk, a change from the previous guideline of age 50. The U.S. Preventive Services Task Force made this update based on rising rates of colorectal cancer in younger adults. Screening continues through age 75, with selective screening for adults 76 to 85.
If you’re 45 or older and haven’t been screened, rectal bleeding is a good reason to get that process started. If you’re under 45 but have symptoms like persistent bleeding, changes in bowel habits, or a family history of colorectal cancer, your doctor may recommend screening earlier.
What to Track Before Your Appointment
If the bleeding isn’t an emergency and you’re planning to see your doctor, come prepared with details. Note how many times you’ve seen blood, whether it’s on the toilet paper, in the bowl, or mixed into the stool, and what color it is. Track whether it happens with every bowel movement or just occasionally. Write down any other symptoms: pain, cramping, fatigue, changes in how often you go, or changes in stool consistency. Also note any recent dietary changes, new medications, or supplements. These details help your doctor narrow down the cause quickly and decide what testing, if any, you need.