Black Stool, Tarry Stool (Melena) in cats

Author: Dr. med. vet. Gisa Löwe | Last modified: 20.02.2026
Table of contents

When to visit the vet?

Emergency see a veterinarian immediately

?

Unsure about what’s wrong with your pet? Feel free to use our Symptom Checker for more clarity

Definition

The term “melena” refers to the occurrence of black, tarry stool in cats. This symptom indicates the presence of digested blood in the stool, often suggesting bleeding in the upper gastrointestinal tract.

Can Occur with the Following Diseases:

Basics and possible causes

Melena occurs when blood from the upper gastrointestinal tract, particularly from the esophagus, stomach, or upper small intestine, is digested. The digestive enzymes and stomach acid change the color of the blood, giving the stool its characteristic black color. The term “tarry” describes not only the color but also the consistency of the stool, which often appears sticky and shiny.

There are numerous potential causes for melena in cats. A common cause is stomach ulcers or duodenal ulcers, which can be caused by medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) or stress. Tumors in the gastrointestinal tract, such as adenocarcinomas or lymphomas, can also cause bleeding. Infections, especially with bacteria such as Helicobacter, can also play a role.

Another possible cause is a blood coagulation disorder, which can be triggered by liver diseases, poisoning, or genetic defects. If the blood does not clot properly, even minor injuries in the gastrointestinal tract can lead to significant bleeding. Traumas, such as swallowing foreign objects, can also lead to injuries and bleeding.

Typical accompanying symptoms

  • Pale gums: Blood loss can lead to anemia, which is recognizable by pale or whitish gums. This is a sign that the cat may not be getting enough oxygen.

  • Vomiting: Bleeding in the stomach can cause Vomiting, which often looks dark or like coffee grounds, indicating digested blood.

  • Loss of appetite: A cat with gastrointestinal discomfort or Pain from ulcers will often refuse to eat.

  • Weight loss: If the cat eats little or nothing over a long period of time, this can lead to significant Weight loss.

  • Weakness or lethargy: Due to the Blood loss and anemia, the cat may appear weak and lethargic because the body is not getting enough oxygen.

  • Abdominal pain: The cat may show signs of discomfort or Pain in the abdomen, such as increased meowing, withdrawal, or Sensitivity to touch.

When to see a vet?

An immediate visit to the veterinarian is necessary if melena occurs, as this may indicate a potentially life-threatening situation. It is particularly urgent if the cat also shows symptoms such as vomiting, pale gums, or extreme weakness. These signs indicate significant blood loss or a serious underlying condition.

Even if melena is the only symptom, the pet owner should not hesitate to consult the veterinarian, as the underlying cause is often serious and difficult to determine without expert diagnosis. The sooner the cause is identified and treated, the better the chances of a full recovery.

Symptom recognition for the pet owner and veterinary diagnostic procedure

It is important for the pet owner to observe the cat’s stool regularly. Black, tarry stool is a clear sign of melena. Changes in the cat’s behavior, such as reduced activity or loss of appetite, should also be taken seriously.

The diagnosis begins with a thorough medical history and physical examination by the veterinarian. Blood tests are essential to determine signs of anemia or coagulation disorders. A stool examination can also be performed to detect blood in the stool. Further investigations may include an ultrasound or X-ray of the abdomen to identify tumors or abnormalities.

In some cases, an endoscopy is required to examine the gastrointestinal tract directly and possibly take tissue samples for biopsy. These procedures help to determine the exact cause of the bleeding and to plan a specific treatment.

What the pet owner can do and professional therapy options

As a pet owner, you can take some measures to make the situation easier for your cat while waiting for the appointment with the veterinarian. Make sure the cat has access to fresh water to avoid dehydration, especially if it is vomiting or has diarrhea.

It is important to calm the cat and keep it in a quiet environment to minimize stress, which could worsen the situation. Avoid giving the cat medication without veterinary advice, as this could worsen the situation, especially if stomach ulcers or blood coagulation disorders are suspected.

Feed the cat easily digestible food if it is willing to eat, so as not to put additional strain on the gastrointestinal tract. Some veterinarians recommend specific diets or feeds that are suitable for cats with gastrointestinal problems, and it may be helpful to consider these.

Collaboration with the veterinarian is crucial to developing the best treatment strategy for your cat and successfully treating the cause of the melena. Depending on the diagnosis, medication, surgical intervention, or a special diet may be necessary to restore your cat’s health.

Outlook on current research

Research on melena in cats is currently focused on improving diagnostic methods to identify the exact source of gastrointestinal bleeding. One of the latest developments is the use of endoscopy and minimally invasive imaging, which allows for detailed examination of the digestive tract without the need for invasive surgical procedures. These technologies help to determine the location of the bleeding more accurately and thus develop more targeted treatment strategies.

Another area of research is the development of specific biomarkers in the blood that can indicate whether melena is triggered by an infection, an ulcer, or another cause. By identifying such biomarkers, early diagnosis could be facilitated and personalized therapy developed. This biomarker research is particularly important because it could help avoid unnecessary treatments and improve the quality of life of affected animals.

Current research is also investigating the role of nutrition in the prevention and treatment of melena. Scientists are exploring how certain dietary changes can help improve the health of the gastrointestinal tract and reduce the risk of internal bleeding. For example, the effect of fiber and probiotics on intestinal health is being studied to determine whether they have a protective effect.

Genetic research is also an emerging field with regard to melena in cats. Researchers are analyzing genetic predispositions that could make certain cat breeds more susceptible to gastrointestinal problems. A better understanding of these genetic factors could, in the long term, lead to breeding healthier cats and reducing the incidence of melena.

Finally, intensive research is being conducted in the field of treatment methods, particularly with regard to the development of new drugs that can accelerate the healing of gastrointestinal mucosal lesions. Research on drugs that promote blood coagulation or regulate stomach acid production could open up new avenues for effectively combating melena.

Frequently asked questions

1. What is melena in cats?
Melena is the medical term for black, tarry stool, which indicates digested blood in the stool. It is a symptom that can indicate bleeding in the upper gastrointestinal tract of a cat.
2. What does melena look like?
Melena appears as shiny, black or very dark stool that has a tarry consistency. The odor can be particularly strong and unpleasant.
3. What are the most common causes of melena in cats?
The most common causes include stomach ulcers, tumors, the use of certain medications such as NSAIDs, and severe infections or inflammatory conditions in the gastrointestinal tract.
4. How is melena diagnosed in cats?
The diagnosis is usually made through a combination of physical examination, blood tests, imaging procedures such as X-ray or ultrasound, and possibly an endoscopy to identify the source of the bleeding.
5. Can melena in cats disappear on its own?
Melena usually requires veterinary treatment, as it is a sign of internal Bleeding that will not heal on its own without appropriate medical intervention.
6. Is melena life-threatening in cats?
Yes, melena can be life-threatening, especially if it is caused by serious conditions such as stomach ulcers or tumors. Rapid diagnostic clarification and treatment are crucial.
7. What treatment options are there for melena in cats?
Treatment may include medications to reduce stomach acid, promote blood coagulation, or treat the underlying cause of the bleeding. In some cases, surgery may be necessary.
8. How can I prevent my cat from developing melena?
Regular veterinary examinations, a balanced diet, and the careful use of medications can help reduce the risk of melena. It is important to avoid known risk factors.
9. How quickly should I act if my cat has melena?
It is important to see a veterinarian immediately if you notice melena in your cat in order to determine the cause and begin appropriate treatment.
10. Can melena be a sign of cancer in cats?
Yes, melena can indicate cancer in the gastrointestinal tract, such as stomach or intestinal tumors. A thorough veterinary examination is necessary to confirm or rule this out.