Black Stool: What Causes It and When Should You Be Concerned?

Sometimes, stool can become so dark that it appears black. In some cases, it may also have a sticky texture resembling asphalt or tar. Black stool can be caused by dietary changes, certain medications, or underlying health conditions that need attention.

Stool color can naturally vary from different shades of brown to yellowish or greenish. These changes are generally influenced by the foods you eat, medications you take, and the amount of bile in your digestive tract. However, black or bright red stool may indicate bleeding. Therefore, even if you suspect that the color change is caused by food or medication, black stool should still be evaluated by a doctor.

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What Causes Black Stool?

Black stool can be caused by bleeding in the digestive tract or by consuming certain foods, medications, and supplements. When the black color is caused by bleeding, the condition is known as melena. The bleeding usually originates from the upper digestive tract, such as the stomach, esophagus, or upper part of the small intestine (duodenum).

Several conditions that can cause bleeding and melena include:

Peptic ulcers: Sores in the lining of the stomach or duodenum that can cause bleeding.
Gastritis or esophagitis: Inflammation of the stomach or esophageal lining that may trigger bleeding.
Erosive gastropathy: Damage or erosion of the stomach lining that can lead to bleeding.
Digestive tract injury or perforation: A tear or hole in the digestive tract wall caused by an injury or certain medical conditions.
Esophageal or gastric varices: Enlarged blood vessels in the esophagus or stomach that can rupture and cause bleeding.
Mallory-Weiss tear: A tear in the lining of the esophagus caused by forceful or repeated vomiting.
Digestive tract cancer: Stomach, esophageal, or pancreatic cancer that may cause bleeding.
Viral hemorrhagic fever: Certain severe viral infections, such as Ebola, can cause bleeding in the digestive tract.

Causes of Black Stool Other Than Bleeding

Not all cases of black stool are caused by bleeding. Certain foods, medications, and supplements can also make stool appear darker, including:

Iron supplements: Taking iron supplements can make stool black or darker than usual.
Medications containing bismuth subsalicylate: This ingredient can cause stool discoloration, making it appear black.
Activated charcoal: Taking activated charcoal can turn stool black.
Dark-colored foods: Eating large amounts of blood sausage, black licorice, or blueberries can change stool color.

Is My Black Stool Caused by Bleeding?

To determine whether black stool is caused by bleeding or simply a color change due to food or medication, doctors may examine a stool sample to check for the presence of blood. They will also ask about your medical history, symptoms, and stool characteristics, including its color, texture, and smell.

Certain characteristics may help distinguish black stool caused by bleeding from stool that has changed color due to food or medication:

Color and texture: Melena typically appears deep black and has a sticky, tar-like texture. Stool that turns black due to food or medication does not necessarily have this sticky consistency. However, certain types of bleeding may also cause loose or diarrhea-like stool. If the amount of blood is small, the stool may appear very dark brown.
Stool odor: Melena usually has a particularly strong and unusual odor. This occurs because the blood is broken down and digested as it passes through the digestive tract. Black stool caused by food or medication generally does not have this characteristic smell.

Although stool color, texture, and odor can provide useful clues, these characteristics alone cannot confirm whether bleeding is occurring. A medical examination is still necessary to determine the cause of black stool.

How Do Doctors Diagnose the Cause of Black Stool?

If a doctor suspects that black stool is caused by bleeding or melena, the examination usually begins with a stool test to detect the presence of blood. One test that may be performed is a fecal occult blood test (FOBT), which detects hidden blood that cannot be seen directly in the stool.

Once bleeding has been confirmed, the doctor may recommend further tests to identify its source and underlying cause. These may include:

Blood tests: Blood tests, including a comprehensive metabolic panel, can help evaluate your overall health, identify possible blood loss, and provide clues about the cause of bleeding.
Imaging tests: A CT scan or CT angiography can help doctors locate the source of bleeding in the digestive tract.
Upper gastrointestinal endoscopy: This procedure uses a thin, flexible tube with a camera that is inserted through the mouth into the esophagus, stomach, and duodenum to identify the source of bleeding. If necessary, the doctor may also take tissue samples or perform procedures to stop the bleeding.

The types of tests performed will depend on the patient’s condition, symptoms, and suspected source of bleeding.

When Should You Be Concerned About Black Stool?

Black stool with a sticky, tar-like texture, especially when accompanied by an unusually strong odor, may indicate melena or bleeding in the digestive tract. This condition should be taken seriously because the bleeding may still be ongoing, even though the blood has already undergone digestion before becoming visible in the stool.

In fact, the blood responsible for black stool may have originated from bleeding that occurred several days earlier. Therefore, do not delay seeking medical attention, even if you are unsure whether the bleeding is still happening.

When Should You Seek Emergency Medical Attention?

Go to the emergency department immediately if black stool is accompanied by signs of significant bleeding, such as:

Vomiting blood: Vomit that is red or resembles coffee grounds.
Dizziness and weakness: Feeling weak, lightheaded, or as if you might faint.
Heart palpitations and shortness of breath: An unusually fast heartbeat accompanied by difficulty breathing.
Black or bloody stool for several days: Repeated episodes may indicate bleeding in the digestive tract.

Evaluation and Treatment for Black Stool at Mandaya Royal Hospital Puri

If you experience black stool, especially if it has a sticky, tar-like texture and a strong odor, you should consult an internal medicine specialist (Sp.PD), particularly a gastroenterology-hepatology subspecialist who treats digestive tract and liver disorders. An examination is necessary to determine whether the stool discoloration is related to bleeding in the digestive tract or another medical condition.

Mandaya Royal Hospital Puri provides diagnostic and treatment services for digestive disorders, supported by a team of internal medicine specialists and gastroenterology-hepatology subspecialists. To help identify the cause of black stool, the hospital also offers endoscopy services, allowing doctors to examine the inside of the digestive tract and detect potential sources of bleeding, such as peptic ulcers or other abnormalities.

With the support of specialist doctors and comprehensive diagnostic facilities, patients can undergo further evaluation to determine the cause of black stool and receive treatment based on their medical condition. Do not delay seeking medical attention, especially if black stool is accompanied by dizziness, weakness, vomiting blood, or severe abdominal pain.

Facilities for Out-of-Town and International Patients at Mandaya Royal Hospital Puri

Mandaya Royal Hospital Puri provides various support facilities to ensure greater comfort for patients traveling from other cities or countries:

VIP transport: A pickup service from Soekarno-Hatta International Airport, train stations, or seaports to the hospital in a comfortable vehicle, accompanied by a Patient Experience Officer (PEO).
Medical ambulance pickup: A dedicated pickup service for patients with specific medical needs from their arrival point (airport, train station, or seaport), equipped with medical equipment and accompanied by professional healthcare personnel.
Accommodation (Sleep Hub and apartments): Comfortable accommodation for patients’ families, located on the 8th floor of the Mandaya Royal Puri building, with nearby apartment options also available.
International Patient Relation: Dedicated assistance for international patients, including medical coordination, interpretation, and administrative support. For information and assistance, contact International Patient Relation at 021 5092 8888 or email [email protected].

To make your visit to Mandaya Royal Hospital Puri easier, use the WhatsApp Chat feature, Book Appointment service, or the Care Dokter application, available for download on Google Play and the App Store. These services allow you to manage your visit, check queue numbers, and access other important information.

The information provided on this page is intended for educational purposes and general guidance. It does not represent the full range of medical services that each doctor may provide. To ensure that you receive care appropriate to your health condition, we recommend consulting the relevant doctor directly.

If you have any questions, suggestions, or need further information, please contact our call center at 0811-1900-2000.