Bloody Stool: Bloody or Tarry Stools: What They Mean & When to Act

Seeing a bloody stool or noticing a black, tarry appearance can be alarming. In many cases, these changes point to bleeding somewhere in the digestive tract. Sometimes the cause is minor, but sometimes it needs urgent medical attention.

The most important thing to know is this: bloody stool and tarry stool are not the same thing, and both can signal different types of gastrointestinal bleeding. Understanding what each one means can help you decide how quickly to act.

It can also help to know that not every dark stool is caused by blood. Foods, supplements, and some medicines can change stool color, which is why the details around texture, smell, and other symptoms matter. If the change is persistent or you feel unwell, the safest choice is to get medical advice.

What bloody or tarry stools mean

Stool color and texture can provide clues about where bleeding may be happening in the digestive system.

– Bloody stool usually means there is visible red blood in or on the stool.
– Tarry stool is typically black, sticky, and foul-smelling. This is often called melena and may suggest bleeding higher up in the digestive tract, such as the stomach or upper small intestine.

These symptoms do not always mean a serious condition, but they should never be ignored. A bloody stool can come from the lower digestive tract, while a tarry stool more often suggests digested blood. The pattern can also help a doctor estimate whether the source is near the anus, in the colon, or higher up in the stomach and small bowel.

In some cases, people notice only a small amount of red blood after wiping, while in others the stool itself looks darker or mixed with blood. Even mild changes can be important if they keep happening.

What does blood in stool look like?

Blood in the stool can appear in different ways:

– Bright red blood on toilet paper or the surface of stool
This often points to bleeding near the rectum or anus.

– Red blood mixed into stool
This may suggest bleeding higher in the lower intestine.

– Black, sticky, tar-like stool
This often means digested blood, which can come from the upper digestive tract.

Sometimes stool color changes happen for reasons unrelated to bleeding. For example, iron supplements, bismuth medications, and certain foods can darken stool. Still, black stool should be taken seriously until a medical cause is ruled out.

If you are unsure whether the color change is normal or a true bloody stool, pay attention to the texture, smell, and any other symptoms such as pain or dizziness. A stool that looks black but is not sticky or foul-smelling may be more likely to come from diet or medication, but it is still worth watching closely if the change is new.

It may also help to note whether the blood appears only on the paper, drips into the toilet, coats the stool, or seems fully mixed in. Those details can help a clinician narrow down the possible source.

Common causes of bloody stool

Bloody Stool can have many causes, ranging from minor to serious. In some people, the issue is brief and linked to constipation. In others, a bloody stool may be the first sign of a condition that needs treatment.

Some causes affect the anus or rectum directly, while others involve the colon or small intestine. The amount of blood can vary from a few streaks to a larger visible amount in the toilet bowl.

Hemorrhoids

Swollen veins in the rectum or anus can bleed, especially during bowel movements. This often causes bright red blood. Hemorrhoids are common and may be linked to straining, pregnancy, sitting for long periods, or chronic constipation.

They can also cause itching, swelling, or discomfort. In many cases, blood from hemorrhoids appears on the tissue or on the outside of stool rather than being fully mixed in.

Anal fissures

A small tear in the lining of the anus can cause pain and bright red bleeding, especially with hard stools. People often describe a sharp or burning pain during bowel movements.

Fissures are more likely when stools are large, dry, or difficult to pass. Improving fiber intake, hydration, and bowel habits can help reduce irritation and prevent repeat bleeding.

Diverticular disease

Small pouches in the colon can bleed or become inflamed, leading to blood in the stool. Diverticular bleeding can sometimes happen suddenly and may be painless.

Some people never know they have diverticula until bleeding or abdominal discomfort develops. A medical exam is important because the amount of bleeding can vary, and other colon problems can look similar.

Inflammatory bowel disease

Conditions such as Crohn’s disease and ulcerative colitis can cause rectal bleeding, diarrhea, abdominal pain, and urgency.

These conditions often come with flares, meaning symptoms may worsen at certain times and then improve. Weight loss, fatigue, and ongoing bowel changes can also happen, especially if the bowel lining remains inflamed.

Infections

Some bacterial or parasitic infections can irritate the intestines and lead to bloody diarrhea.

Infection-related bleeding may come with fever, cramping, nausea, vomiting, or recent travel and food exposure. Because some infections spread easily, doctors may order stool testing when diarrhea and blood happen together.

Polyps or colorectal cancer

Growths in the colon or rectum can sometimes bleed. This is one reason persistent rectal bleeding should always be evaluated. If the bleeding is recurrent, a bloody stool should not be dismissed as a harmless one-time event.

While many cases of bleeding are caused by less serious problems, ongoing blood loss can also be a warning sign of colon polyps or cancer. That is why age, family history, and changes in bowel habits matter so much during evaluation.

Upper gastrointestinal bleeding

Bleeding from the stomach or small intestine can sometimes pass through the digestive system and cause black, tarry stool or, in some cases, dark red stool. One helpful related resource is this guide to blood in stool, lower back pain & fatigue: causes explained.

Upper GI bleeding can come from ulcers, inflammation, tears, or blood vessel problems. If the bleeding is slow, the stool may become black rather than bright red because the blood has had time to travel and change as it moves through digestion.

Common causes of tarry stool

Black, tarry stool usually suggests old blood that has been partially digested. Common causes include:

Stomach ulcers

Ulcers can bleed and may cause melena.

Ulcers may be related to infection with H. pylori or the use of NSAIDs, which can irritate the stomach lining. Burning pain in the upper abdomen, nausea, and symptoms that worsen when the stomach is empty are sometimes reported as well.

Gastritis

Inflammation of the stomach lining can lead to bleeding, especially with alcohol use, NSAID use, or infection.

Gastritis may develop slowly or suddenly. Some people notice indigestion, upper abdominal discomfort, bloating, or vomiting before stool color changes appear.

Esophageal tears or varices

Tears in the esophagus or enlarged veins in the esophagus can bleed heavily and may produce black stool.

These causes can be serious. Vomiting blood, chest discomfort, or liver disease symptoms may point toward a higher-risk problem and require urgent assessment.

Medications

Some medications, especially iron supplements and bismuth subsalicylate, can cause black stool that is not due to bleeding. Even so, if the stool is truly tarry or you have other symptoms, medical evaluation is still important.

For more background on medications that affect bleeding risk, see the NHS medicines information pages for general guidance on side effects and safe use.

Other medicines may also raise bleeding risk indirectly by irritating the stomach or affecting clotting. People who take blood thinners, frequent pain relievers, or steroids should be especially alert to new stool changes and other bleeding symptoms.

When bloody or tarry stool is an emergency

Seek emergency medical care right away if bloody or tarry stool is accompanied by any of the following:

– Large amounts of blood
– Dizziness or fainting
– Weakness
– Shortness of breath
– Severe abdominal pain
– Rapid heartbeat
– Vomiting blood or material that looks like coffee grounds
– Pale skin or signs of shock
– Black stool with severe illness or confusion

These symptoms may indicate significant internal bleeding. A bloody stool with weakness or fainting should be treated as urgent.

Heavy bleeding can lower blood pressure quickly and may cause sweating, confusion, or a feeling that you might pass out. If symptoms are severe or worsening, do not wait to see if they improve on their own.

When to call a doctor soon

You should contact a healthcare provider promptly if you notice:

– Blood in the stool that keeps happening
– Black stool without a clear explanation
– Blood mixed into diarrhea
– Abdominal pain, weight loss, or fatigue
– Changes in bowel habits
– A personal or family history of colon polyps, colon cancer, or inflammatory bowel disease

Even if the bleeding seems small, repeated episodes should be checked. A small bloody stool today can still matter if it continues for several days.

It is also important to get checked if you are older, have anemia, take a blood thinner, or have other medical problems that make bleeding more dangerous. In these situations, even a small amount of blood can become more significant.

How doctors evaluate bloody or tarry stools

A doctor will usually start by asking about your symptoms, medications, diet, and medical history. They may also perform a physical exam and order tests to find the source of bleeding.

Common tests include:

– Stool tests to check for hidden blood or infection
– Blood tests to look for anemia or signs of blood loss
– Endoscopy to examine the upper digestive tract
– Colonoscopy to inspect the colon and rectum
– Imaging tests if the bleeding source is not clear

The right test depends on your symptoms, age, and risk factors. If a bloody stool is caused by a problem in the upper tract, an endoscopy may be more useful than a colon exam.

Doctors may also ask about recent travel, new medications, alcohol use, and whether you have pain during bowel movements. If you are having repeated episodes, they may want to know how much blood you see and whether the stool is black, red, or maroon.

Sometimes, the evaluation is straightforward. Other times, multiple tests are needed to locate the bleeding source and determine whether treatment should focus on the stomach, intestines, anus, or another part of the digestive tract.

How to tell if stool color is from blood or something else

Not every dark stool means bleeding. Some common non-bleeding causes include:

– Iron supplements
– Pepto-Bismol or similar medications
– Blueberries, black licorice, or dark foods
– Certain antibiotics or supplements

Bright red stool can also sometimes come from foods like beets or red food coloring.

If you are unsure whether the color change is from food, medication, or blood, it is safest to contact a healthcare professional, especially if the stool is black and sticky or the symptom is recurring. A true bloody stool is more likely when the color is persistent and accompanied by pain, weakness, or changes in bowel habits.

A simple question to ask yourself is whether the color change happened after a new food, supplement, or medicine. If the answer is yes, watch closely for a day or two. If the stool remains black or red, or if you feel worse, get checked sooner.

What not to do

If you notice bloody or tarry stool:

– Do not ignore repeated symptoms
– Do not assume it is only hemorrhoids without being checked
– Do not take NSAIDs such as ibuprofen or naproxen unless a doctor says they are safe, as they can worsen bleeding
– Do not wait if you feel weak, faint, or short of breath

It is also wise not to self-diagnose every episode of bloody stool, because several conditions can look similar at first.

Do not use laxatives, antibiotics, or stomach remedies to cover up symptoms unless they were recommended by a clinician. Treating the symptom without finding the cause can delay important care.

Can bloody or tarry stool go away on its own?

Sometimes minor bleeding, such as from a small fissure or hemorrhoid, may improve with time and better bowel habits. However, black tarry stool is more concerning because it often points to bleeding higher in the digestive tract.

Even if symptoms seem to go away, the cause may still need treatment. Ongoing or unexplained bleeding can lead to anemia and may signal a condition that needs medical care. A bloody stool that stops and starts again should still be evaluated.

If the problem is linked to constipation, improving stool softness and reducing straining may help. But if bleeding keeps returning, the person should not assume it is harmless just because it comes and goes.

How to reduce your risk of digestive bleeding

Not all causes can be prevented, but these habits may lower your risk:

– Eat enough fiber and drink plenty of water to avoid constipation
– Avoid straining during bowel movements
– Use NSAIDs only when necessary and as directed
– Treat acid reflux, ulcers, or stomach irritation early
– Follow up on any ongoing digestive symptoms
– Get recommended colon cancer screening based on age and risk

People with a history of a bloody stool should also watch for recurring symptoms and follow medical advice closely, especially if they have known digestive conditions.

Other helpful habits include limiting alcohol if it irritates your stomach, taking prescribed medicines as directed, and getting prompt care for infections that cause diarrhea or abdominal pain. If you already have a condition that raises bleeding risk, regular follow-up can help prevent complications.

For people taking blood thinner medications, even small bleeding symptoms deserve attention because those medicines can make bleeding harder to stop.

When to get urgent care for bloody stool

Some symptoms mean you should act quickly rather than waiting for a routine appointment. Get urgent help if the bleeding is sudden, the amount is large, or the stool is black and accompanied by pain, fainting, or vomiting. A bloody stool with severe weakness should always be treated as a medical warning sign.

If you are alone and feel lightheaded, avoid driving yourself. Call emergency services or ask someone to take you to the nearest emergency department. Bring a list of your medicines if possible, especially if you take aspirin, anti-inflammatory drugs, or blood thinners.

Questions doctors often ask

When evaluating a bloody stool, a clinician may ask:

• When did you first notice the blood or black stool?
• Is the blood bright red, dark red, or black and tarry?
• Do you have pain, fever, nausea, or diarrhea?
• Have you taken iron, bismuth, aspirin, or NSAIDs?
• Do you have constipation or hard stools?
• Have you lost weight or felt unusually tired?
• Is there a family history of colon cancer, polyps, or inflammatory bowel disease?

These questions help separate common causes from more serious ones. If you can answer them before your visit, it may make the evaluation easier and faster.

Key takeaways

Bloody Stool and tarry stool can both be signs of bleeding in the digestive tract, but they often point to different sources.

– Bright red blood often comes from the lower digestive tract or the anus.
– Black, tarry stool often suggests bleeding in the upper digestive tract.
– Some medications and foods can mimic these stool changes, but true bleeding should not be ignored.
– Emergency care is needed if bleeding is heavy or comes with dizziness, weakness, vomiting blood, or severe pain.
– If the symptom is persistent, unexplained, or recurring, see a doctor promptly.

When it comes to a bloody stool or tarry stool, the safest approach is to treat it as a warning sign until a healthcare professional determines the cause. A timely checkup can help rule out serious disease and guide the right treatment.