Mar. 14, 2025

Dark Brown Diarrhea: What It Means & When It’s Serious

Young Bo Sim, MD

Physician

General Medicine / Resources /

Dark Brown Diarrhea: What It Means & When It’s Serious

Digestive health

woman sitting on dock looking at town on water's edge with hills in the background

Dark brown diarrhea can have many causes, some of which are more serious than others and can potentially be life-threatening.
The presence of certain features may imply the need for an urgent evaluation by a healthcare professional.
The causes of dark brown diarrhea vary based on whether your symptoms are acute or chronic.

Dark brown diarrhea can be a startling experience. There are many possible causes of dark brown diarrhea, and they range in severity from minor to those that can drastically reduce your quality of life.

Fortunately, for minor cases, there are treatment options that you can try at home. However, you may require evaluation from a healthcare professional if you notice certain features or if your symptoms do not improve over time. Certain causes can lead to more complications if untreated, and your primary care provider may suggest a referral to a gastroenterologist, a professional who specializes in the stomach and digestive tract.

Is dark brown diarrhea normal?

Dark brown diarrhea can be normal. Perhaps you have eaten something that went bad, and your symptoms may have only occurred a few times.

Regardless, diarrhea is a frustrating symptom to deal with, and it can be difficult to determine whether the color of your diarrhea is a reason for alarm or not. There are multiple possible causes of dark brown diarrhea, and some of these causes may prompt urgent evaluation from your primary care provider or a healthcare professional.

Common causes of dark brown diarrhea

The color of diarrhea can vary tremendously from nearly clear to bright red, tarry black, and every color in between. Dark brown may be a normal color for diarrhea, similar to your normal bowel movements, although looser in consistency. However, dark brown may also suggest more serious causes. Some of the common causes of dark brown diarrhea are discussed below.

Gastroenteritis

The most common cause of diarrhea in general, including dark brown diarrhea, is viral gastroenteritis (stomach flu), a viral infection that leads to inflammation of the GI tract. Numerous viruses can cause viral gastroenteritis, including norovirus and rotavirus, among others. Similarly, bacteria can also cause gastroenteritis, although this may lead to slightly different and perhaps worse symptoms.

Some factors that increase your risk of getting gastroenteritis include ingestion of spoiled or contaminated foods, contact with people who are sick with similar symptoms, recent travel via cruise ship, and swimming in contaminated water. You can also develop gastroenteritis if you have recently had a cold, viral upper respiratory infection (URI), or other illness.

Inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) can also lead to dark brown diarrhea. IBD refers to any diagnosis that is associated with inflammation of the intestines, although it is commonly used to describe two specific diagnoses: Crohn’s disease and ulcerative colitis. These two diagnoses vary slightly in presentation, patient age, and which parts of the GI tract are affected.

The underlying inflammation associated with IBD can also cause other symptoms, such as fever, weight loss, blood in your stool, abdominal pain, and fatigue. The dark brown color of your diarrhea may be due to blood mixed into your stools, and you may experience looser stools due to inflammation.

If you have any family members with a history of IBD, you may be at increased risk of developing IBD. Certain individuals are at increased risk of developing IBD, so if you experience some of the symptoms noted above alongside dark brown diarrhea, speak with your primary care provider to establish the diagnosis.

Bleeding

Blood mixed into your stool can cause diarrhea to appear dark brown. The location and cause of the bleeding will affect the color of your bowel movements, as bright red blood is indicative of bleeding lower in the GI tract, such as the colon or closer to the anus. This is known as hematochezia.

A darker color, often described as tar-like or black, may represent bleeding from higher up in the GI tract, such as the stomach or small intestine, and this is referred to as melena. You may also have different sources of bleeding, such as hemorrhoids, polyps, fissures, or even from other sources, such as a nosebleed if you have swallowed enough blood.

Food or medications

Contaminated foods or liquids may cause gastroenteritis, and medications can also lead to the development of dark brown diarrhea. Certain foods such as black licorice, blood sausage, or blueberries may lead to dark brown or even black stools. Beets and other foods with red coloring can cause red discoloration of your stools. Some medications can cause similar discoloration, such as iron supplementation and Pepto-Bismol.

What dark brown diarrhea may mean based on appearance, consistency, or another symptom or condition

Below are descriptions of different incidences of dark brown diarrhea and what they may mean in the presence of accompanying symptoms or conditions.

Very dark, blackish diarrhea: This may suggest bleeding.
Dark brown, watery diarrhea: This is more likely to suggest gastroenteritis or other inflammation that is affecting your body’s ability to hold onto liquid.
Dark brown diarrhea accompanied by stomach cramps: This is a non-specific combination that does not correlate to one specific diagnosis or condition.
Dark brown diarrhea that occurs right after eating: This is likely to result from food poisoning or food ingestion that causes gastroenteritis.
Dark brown diarrhea that occurs after drinking alcohol: This is likely due to alcohol and its metabolism affecting your GI tract.
Dark brown diarrhea that occurs during pregnancy: This may be due to multiple factors during pregnancy, such as hormonal changes, stress, or food sensitivities.

Read our guide on stool color meanings for more.

When to see a doctor about dark brown diarrhea

Dark brown diarrhea can be caused by multiple conditions. If you experience any of the symptoms or features noted below, you should seek further evaluation by a doctor or go to the ER.

You should see a doctor if:

Your symptoms occur frequently, or the volume of your bowel movements continues to increase despite the use of common treatment options.
You notice weight loss.
You have significant changes in appetite.
You experience worsening abdominal pain.
You experience any of the following features:
- Symptoms begin after 50 years of age.
- Rectal bleeding or melena - black, tarry stools.
- Pain or diarrhea during the night.
- Fever.
- A close relative with IBD or colorectal cancer.

You should go to the emergency room if:

You notice bright red blood in your bowel movements or black, tarry stools.
You experience sudden, unresolved dizziness.
You experience ongoing or unresolved palpitations, which are the sensation of a racing heart.
You start vomiting blood.
You are unable to keep down food or liquids.

Questions to ask your doctor about dark brown diarrhea

Should I obtain blood work, stool studies, or other workup to assess my dark brown diarrhea?
Is there a need for imaging, such as CT or MRI?
Should I obtain an endoscopy, such as an esophagogastroduodenoscopy (EGD) or a colonoscopy?
What other treatment options or medications may help address my symptoms?

How to stop or treat dark brown diarrhea

There are many possible causes of dark brown diarrhea. Therefore, there are multiple treatment options that you can try at home.

These treatment options may not always work, and if you have little improvement in your symptoms, you should speak with your primary care provider. If you have chronic medical conditions, discuss these medications with your primary care provider and always follow manufacturer directions.

Fiber supplementation

Fiber is a great way to help treat diarrhea. There are many fiber-rich foods, such as certain fruits, vegetables, lentils, grains, and beans, which may help with your diarrhea and also improve your general health.

Pepto-Bismol

Even though Pepto-Bismol is one of the medications that may cause black stools, it is also an option to treat dark brown diarrhea. It is important to keep in mind that it may cause further discoloration of your bowel movements, although it is worth considering as a treatment for your diarrhea.

Imodium and other gut motility medications

Diarrhea is often caused by improper absorption of food and drinks by your intestines. There are many medications, such as Imodium, which can help treat diarrhea by slowing down your gut and intestines so that food is processed more thoroughly. If you have chronic medical conditions, always discuss these medications with your primary care provider and follow manufacturer directions.

How to prevent dark brown diarrhea

Although treating dark brown diarrhea is important while you’re experiencing symptoms, preventing it in the first place can have a larger positive impact on your health. Below are simple strategies that may help prevent the development of dark brown diarrhea.

Minimizing stress

Stress can negatively impact your body in many ways, including by causing dark brown diarrhea. Minimizing stress as much as possible is an important step toward addressing diarrhea and other stress-related conditions.

Better understanding your response to stressors and avoiding unnecessary stress can improve your health overall. Exercise and other stress-reducing hobbies are good things to participate in.

Dietary changes

Certain foods may be triggering your symptoms. If you notice a particular food or group of foods that seem to be associated with the onset or worsening of your symptoms, adjust your diet to avoid them. You can discuss specific recommended diets with your primary care provider.

Hydration

If you are experiencing dark brown diarrhea, you may be losing a lot of water through your stool. Staying adequately hydrated is important not only to help treat but also to prevent the development of symptoms. When dealing with dark brown diarrhea, drink plenty of fluids and electrolyte-containing beverages, such as Gatorade.

Frequently asked questions: dark brown diarrhea

Dark brown diarrhea can be confusing to understand. Here are some frequently asked questions about dark brown diarrhea.

What should you eat or drink immediately after having dark brown diarrhea?

If there is a specific food that you notice is causing or worsening your symptoms, avoid that food. Immediately after having dark brown diarrhea, focus on hydration first and find foods that you can tolerate without making symptoms worse. Avoid foods that are greasy, spicy, or acidic.

Can you treat dark brown diarrhea at home?

Yes, you can use some of the treatment methods outlined above to treat dark brown diarrhea at home. If these don’t work, you may consider getting prescription medications from your primary care provider or other healthcare professional.

Better understand, control, and prevent your dark brown diarrhea

No one enjoys having diarrhea. When it’s dark brown, the color may cause you further stress. In most cases, dark brown diarrhea will resolve on its own, but if you notice that your symptoms are persistent or worsening despite attempted treatment, you should speak with your primary care provider.

General Medicine follows a strict editorial process, including using real experts to write our articles, vetted primary sources, fact-checking, a secondary medical review, and updates as necessary. This article was medically reviewed and fact checked by Dr. Lane Thaut, DO.