Can Worms Cause Black Stools in Cats? Understanding the Signs
Cats are known for their stoic nature and often do not show clear signs when they are unwell. One of the most useful indicators of feline health is their feces. By paying close attention to the
color, consistency, frequency, and content of a cat’s stool, pet owners can detect issues that may require veterinary attention. Among these signs,
black stools, also known as
melena, are particularly concerning.
What Does Normal Cat Poop Look Like?
A healthy cat’s stool is typically:
- Dark brown in color
- Shaped like a log or sausage
- Firm but pliable in consistency
- Segmented and leaves minimal to no residue when scooped
Adult cats usually defecate once or twice daily, while kittens may do so up to five times, and senior cats might go less frequently.
What Is Melena?
Melena refers to black, tarry stools and typically indicates bleeding in the upper gastrointestinal tract — which includes the mouth, esophagus, stomach, or small intestine. This bleeding leads to
digested blood entering the stool, turning it dark and shiny. Melena is different from red-streaked blood, which signals lower GI tract bleeding.
Can Worms Cause Black Stools?
Yes, certain
intestinal parasites such as hookworms can cause black stools in cats. These parasites attach to the lining of the gastrointestinal tract and feed on the host’s blood, which may result in internal bleeding. The digested blood darkens the stool, leading to the characteristic black, tar-like appearance.
Other Symptoms of a Worm Infestation
Alongside black stools, other signs of parasitic infection in cats may include:
- Vomiting
- Diarrhea
- Weight loss despite normal or increased appetite
- A distended or bloated abdomen
- Lethargy
- Visible worms or white spots in feces
White spots may appear as
rice-like grains (tapeworms) or
spaghetti-like strands (roundworms) in the cat’s stool or near the anus.
Other Causes of Black Cat Stool
Besides worms, several other conditions can result in melena:
- Ulcers in the stomach or upper intestines
- Tumors causing internal bleeding
- Ingestion of certain toxins, such as rodenticides
- Side effects of medications, particularly NSAIDs
- Bile duct or liver problems, which affect digestion
- Retention of old or dried feces due to constipation
- Raw or dyed foods causing temporary color changes
When to See the Vet
If a cat’s stool is black and tarry, it is a potential emergency. Pet owners should contact a veterinarian immediately, especially if the condition is accompanied by:
- Lethargy or significant behavior changes
- Lack of appetite
- Pale gums
- Vomiting or diarrhea
- Signs of pain or discomfort
A vet may request a fresh stool sample for diagnostic testing and may perform blood tests, X-rays, or an ultrasound to determine the source of internal bleeding or infection.
Prevention and Monitoring
Guarding against parasite infections and other health issues involves several proactive steps:
- Perform routine vet checkups and maintain up-to-date deworming schedules.
- Offer a nutritionally balanced diet and ensure your cat has access to clean, fresh water.
- Monitor your cat’s litter box regularly, noting changes in feces color, consistency, or frequency.
- Avoid abrupt food changes or treats known to affect digestion.
- Maintain a clean litter environment to prevent infections and behavioral stress.
Conclusion
Yes, worms — particularly hookworms — can cause black stools in cats by inducing internal bleeding in the upper GI tract. Such symptoms should never be ignored. Regular monitoring of your cat’s stool, timely deworming, and prompt veterinary care are essential to ensuring your feline friend’s long-term health and comfort. Always consult your vet if any changes in stool color or behavior arise.
