Introduction: Should You Be Concerned About Blood in Your Stool?
Finding blood in your stool is alarming — and it should get your attention. But it doesn’t automatically mean the worst. Blood in stool is one of the most common reasons patients visit a gastroenterologist, and the causes range from something as straightforward as a hemorrhoid to conditions that require immediate medical intervention.
What matters most is not panicking, but also not ignoring it.
At Colon & Digestive Health Specialists in Conyers, GA, our board-certified gastroenterologists evaluate rectal bleeding and gastrointestinal bleeding regularly. This guide gives you medically accurate, straightforward information — what the blood actually looks like, what’s causing it, which symptoms demand urgent care, how doctors diagnose it, and what treatment looks like depending on the underlying condition.
What Does Blood in Stool Look Like?
This is the first question most patients ask — and the answer matters clinically, because the color and consistency of the blood tells your gastroenterologist a great deal about where in your digestive tract the bleeding is coming from.
Bright Red Blood
Bright red blood in stool — on toilet paper, in the toilet bowl, or coating the outside of stool — typically signals bleeding in the lower digestive tract: the rectum, anus, or lower colon. This is the most common presentation and is frequently caused by hemorrhoids or anal fissures.
Bright red blood is “fresh” — it hasn’t traveled far through the digestive system before you see it.
Dark Red or Maroon Blood
Dark red or maroon-colored blood mixed into the stool usually indicates bleeding from the mid to upper colon or from the small intestine. The blood has traveled further through the digestive tract, giving it a darker appearance.
This presentation is more concerning than bright red blood and warrants prompt medical evaluation.
Black, Tarry Stools (Melena)
Black, tarry, or sticky stools with a distinctly foul odor — called melena — indicate bleeding in the upper gastrointestinal tract: the esophagus, stomach, or upper small intestine (duodenum). The blood has been partially digested as it moved through the GI tract, turning it black.
Melena is a medical concern and should always be evaluated by a physician. Do not wait to see if it resolves on its own.
Occult Blood (Invisible)
Sometimes, blood in stool is not visible to the naked eye at all. This is called occult blood — hidden bleeding that can only be detected through a laboratory test called a fecal occult blood test (FOBT) or a fecal immunochemical test (FIT). This is why routine colorectal cancer screening matters — occult bleeding from polyps or early tumors produces no visible symptoms.
Blood may occasionally be completely invisible, in which case a fecal occult blood test is necessary to detect it.
What Can Cause Bleeding in Stool?
Rectal bleeding and gastrointestinal bleeding have many potential causes. Understanding the most common ones helps you have a more informed conversation with your doctor.
1. Hemorrhoids
Hemorrhoids — swollen veins in the rectum or anus — are the most common cause of bright red rectal bleeding in adults. They can be internal (inside the rectum) or external (under the skin around the anus).
What it looks like: Bright red blood on toilet paper, coating the outside of stool, or dripping into the toilet bowl. Usually painless with internal hemorrhoids; external hemorrhoids may cause pain, itching, or swelling.
Who gets them: Anyone, but risk increases with chronic constipation, straining during bowel movements, pregnancy, a low-fiber diet, and prolonged sitting.
Key point: Hemorrhoids do not cause black or dark tarry stools. If your stool is dark, another cause needs to be investigated.
2. Anal Fissures
An anal fissure is a small tear in the lining of the anal canal — similar to a paper cut, but in a very sensitive location. Fissures are extremely common and are typically caused by passing hard, large, or dry stools.
What it looks like: Bright red blood on toilet paper, often accompanied by sharp pain or burning during and after a bowel movement. Unlike hemorrhoids, anal fissures are almost always painful.
Who gets them: People with chronic constipation, those who strain excessively during bowel movements, and postpartum women.
3. Diverticular Bleeding
Diverticulosis refers to small pouches (diverticula) that form in the walls of the colon. Most diverticula never cause problems — but occasionally, a blood vessel near a pouch ruptures, causing diverticular bleeding, which can be significant.
What it looks like: Sudden, painless passage of a large amount of bright red or dark red blood from the rectum. This type of bleeding can be dramatic and may require hospitalization.
Who gets them: More common in adults over 50 and those with a history of diverticulosis. Diverticular bleeding is one of the most common causes of lower GI bleeding in older adults.
Important note: Diverticular bleeding often stops on its own, but it can recur and sometimes requires intervention.
4. Colorectal Polyps and Colorectal Cancer
Colorectal polyps are abnormal growths on the lining of the colon or rectum. Most polyps are benign, but certain types — particularly adenomas — can become cancerous over time if not removed.
What it looks like: Polyps typically bleed slowly and in small amounts. The blood may be bright red, dark, or entirely occult (invisible). This is why routine colonoscopy screening is so critical — polyp bleeding often produces no noticeable symptoms until the disease is advanced.
Colorectal cancer can also cause rectal bleeding, changes in bowel habits, unexplained weight loss, and fatigue. It is the third most commonly diagnosed cancer in the United States.
5. Inflammatory Bowel Disease (IBD)
Inflammatory bowel disease — which includes Crohn’s disease and ulcerative colitis — causes chronic inflammation of the digestive tract that can lead to rectal bleeding, diarrhea, abdominal cramping, and fatigue.
What it looks like: Blood mixed in with loose or watery stool, often accompanied by urgency, cramping, and mucus in the stool. IBD bleeding tends to be recurrent rather than a single episode.
Who gets it: IBD most commonly develops in people between ages 15 and 35, though it can occur at any age. It is a chronic condition that requires ongoing management with a gastroenterologist.
6. Peptic Ulcers
Peptic ulcers are open sores that develop on the lining of the stomach or upper small intestine (duodenum). They are most commonly caused by infection with Helicobacter pylori bacteria or long-term use of NSAIDs (such as ibuprofen or aspirin).
What it looks like: Upper GI bleeding from a peptic ulcer typically produces black, tarry stools (melena) or, in severe cases, vomiting blood (hematemesis). Some patients also experience burning stomach pain, nausea, and bloating.
7.Gastrointestinal Infections
Bacterial, viral, or parasitic infections can inflame the intestinal lining and cause infectious colitis, which may lead to bloody diarrhea.
Common causes include Campylobacter, Salmonella, Shigella, E. coli O157:H7, and Clostridioides difficile (C. diff). C. diff infection is particularly common after antibiotic use.
What it looks like: Bloody or mucousy diarrhea, often accompanied by fever, abdominal cramping, and nausea. Usually has a clear triggering event (recent antibiotic use, travel, food exposure).
Blood in Stool With No Pain — Is It Serious?
One of the most common questions patients ask is: “I’m not in any pain — does that mean it’s not serious?”
The answer is no — painless rectal bleeding should not be dismissed.
Hemorrhoids and diverticular bleeding are both typically painless but require evaluation. More importantly, colorectal cancer and polyps almost never cause pain in early stages. The absence of pain is not a reassuring sign when it comes to GI bleeding — it simply means you haven’t yet developed a complication that causes pain.
Bright red, painless rectal bleeding in a person over 45 with no prior colonoscopy should prompt a medical evaluation regardless of how minor it seems.
Signs of Internal Bleeding You Shouldn’t Ignore
Internal bleeding symptoms may not always include visible blood. Watch for:
- Weakness or fatigue
- Dizziness or fainting
- Paleness
- Abdominal pain or cramping
- Black, tarry stools
- Rapid heart rate
These are severe warning indicators that could point to a large amount of blood loss, potentially from a tumor, gastrointestinal perforation, or bleeding ulcer.
When to Worry About Blood in Stool
While some cases are harmless, it’s crucial to know when to worry about blood in stool:
- The bleeding is continuous or frequent.
- Additionally, you’re feeling exhausted, losing weight, or having stomach pain.
- You have tarry, dark stools.
- You have not had a colonoscopy and are over 50.
- A history of colorectal cancer runs in your family.
Schedule a Routine Evaluation If:
- You have a single episode of small-volume bright red bleeding with a clear likely cause (e.g., known hemorrhoids, recent constipation)
- You have no other accompanying symptoms
- You are due for routine colorectal cancer screening
Blood in Stool During Pregnancy
Rectal bleeding during pregnancy most commonly results from hemorrhoids, which are extremely common due to increased pelvic pressure and constipation, and anal fissures from straining. While these causes are typically benign, any rectal bleeding during pregnancy should be reported to your OB/GYN or gastroenterologist.
Blood in stool during pregnancy should never be self-diagnosed. Both the timing and the type of bleeding matter for safe evaluation
How Doctors Diagnose the Cause of Blood in Stool
A thorough diagnostic workup is essential — blood in stool is a symptom, not a diagnosis. Your gastroenterologist will use a combination of approaches:
1. Medical History and Physical Examination
Your doctor will ask detailed questions about the bleeding: color, frequency, amount, associated symptoms, family history, and medications. A physical exam including a digital rectal exam can identify hemorrhoids, fissures, and masses near the anal canal.
2. Fecal Occult Blood Test (FOBT) or Fecal Immunochemical Test (FIT)
These tests detect blood in stool that is invisible to the naked eye. A positive result means blood is present — but it does not identify the source. A positive FOBT or FIT always requires follow-up with a colonoscopy.
3. Colonoscopy
A colonoscopy is the gold-standard diagnostic tool for evaluating rectal bleeding and lower GI bleeding. Using a flexible, camera-equipped tube, your gastroenterologist can visualize the entire colon and rectum, identify the bleeding source, take biopsies of suspicious tissue, and remove polyps — all in a single procedure.
Colonoscopy is the only test that is simultaneously diagnostic and therapeutic for lower GI bleeding.
4. Upper Endoscopy (EGD)
When black tarry stools or vomiting blood suggest upper GI bleeding, an upper endoscopy (EGD) is performed. A flexible scope is passed through the mouth into the esophagus, stomach, and upper small intestine to identify and treat bleeding sources like ulcers or varices.
5. Imaging Examinations: To find anomalies in your intestines, you might need to have barium studies or CT scans.
Prevention: Reducing Your Risk of GI Bleeding
While not all causes of rectal bleeding are preventable, several evidence-based lifestyle choices meaningfully reduce your risk:
Eat a high-fiber diet. Fiber softens stool, reduces straining, lowers colonic pressure, and decreases the risk of hemorrhoids, anal fissures, and diverticular disease. Aim for 25–38 grams of fiber daily from fruits, vegetables, whole grains, and legumes.
Stay well hydrated. Adequate water intake works alongside fiber to keep stool soft and easy to pass. Dehydration is one of the most common contributors to constipation-related bleeding.
Avoid prolonged straining. Straining on the toilet increases pressure on rectal veins and the anal lining. If you’re straining regularly, address the underlying constipation rather than pushing through it.
Use NSAIDs cautiously. Long-term or excessive use of ibuprofen, aspirin, or naproxen significantly increases the risk of peptic ulcers and upper GI bleeding. If you need regular pain relief, discuss safer alternatives with your physician.
Do not smoke. Smoking is an independent risk factor for peptic ulcers, Crohn’s disease, and colorectal cancer.
Get screened on schedule. Colonoscopy screening starting at age 45 (or earlier with family history) prevents colorectal cancer by identifying and removing precancerous polyps before they progress. It is the single most powerful intervention available.
Manage chronic conditions. IBD, diverticulosis, and peptic ulcer disease all increase bleeding risk when poorly controlled. Regular follow-up with your gastroenterologist helps keep these conditions managed.
When to See a Gastroenterologist for Blood in Stool
Rectal bleeding is your body’s way of signaling that something in your digestive tract needs attention. Whether the cause is minor or serious, the only way to know for certain is through professional evaluation by a gastroenterologist — not by waiting, self-diagnosing, or assuming it will resolve.
See a gastroenterologist promptly if:
- You notice blood in your stool for the first time
- Bleeding recurs even after seeming to stop
- You are 45 or older and not current on colorectal cancer screening
- You have a family history of colorectal cancer, polyps, or IBD
- Blood in stool is accompanied by any change in bowel habits, unexplained weight loss, or fatigue
- You have black or tarry stools of any amount
FAQs
Q.1 Is blood in stool always cancer?
No. It’s often due to hemorrhoids or fissures, but it’s always wise to investigate.
Q2. Can stress cause blood in stool?
Stress may worsen IBD, which could lead to bleeding, but it’s rarely a direct cause.
Q3. How is blood in stool treated?
Treatment depends on the diagnosis—it ranges from lifestyle changes to medication or surgery.
Q4. Should I go to the ER for blood in stool?
Go to the ER if you’re fainting, dizzy, or notice heavy bleeding.
Care at Colon & Digestive Health Specialists
At Colon & Digestive Health Specialists, we are committed to providing expert, compassionate care for patients experiencing bleeding in the stool. Our experienced gastroenterology team uses advanced diagnostic methods to identify the underlying cause—whether it’s hemorrhoids, polyps, ulcers, or more serious conditions—and creates a personalized treatment plan to ensure optimal recovery.
Prompt evaluation is essential when blood is present in your stool, as early diagnosis can prevent complications and improve outcomes. Don’t ignore the warning signs—schedule a consultation today and let our specialists help you restore and protect your digestive health for a healthier, worry-free future.
Dr. Karim Shakoor, M.D. is a board-certified gastroenterologist and founder of Colon & Digestive Health Specialists, LLC. He completed his residency and fellowship at Cook County Hospital, which is known for having one of the most extensive programs in the country. Karim Shakoor, M.D. is dedicated to providing his patients with the highest level of care to improve their quality of life. He specializes in the treatment of digestive disorders, including abdominal pain, colon cancer, constipation, diarrhea, diverticulitis, gas, gastrointestinal bleeding, heartburn, irritable bowel syndrome, peptic ulcers, swallowing difficulty, and ulcerative colitis.