Half Gum Mystery. Why is My Cat’s Gum Black on One Side?

What Does Black Gum Mean in Cats?

Black gums in cats can be caused by several conditions, some harmless and others more serious. Common reasons for black pigmentation on a cat’s gums include:

  • Lentigo – A benign condition where black spots appear on the gums, lips, nose and eye margins of light colored cats. It is not harmful and requires no treatment (Source).
  • Melanin pigmentation – Darker skinned cats can develop more melanin in their gums as they age, causing blackening. This is a normal change (Source).
  • Oral melanomas – Cancerous melanin-producing tumors in the mouth, quite rare but aggressive. Seen as raised black growths on the gums (Source).
  • Gingivitis/Periodontal disease – Inflammation and infection can cause gums to turn black as tissue dies. The gums recede, exposing blackened roots of teeth (Source).

If the black color appears suddenly, is only on one side, or is accompanied by gum swelling, it warrants an exam by a veterinarian to diagnose the cause.

Is Black Gum Disease Dangerous?

Black gum disease is not typically dangerous on its own and more often represents a benign skin condition called lentigo that causes harmless black spots to appear on a cat’s gums, nose, and eye margins (Cats Inn, 2023). However, black gums can sometimes indicate an underlying health issue that requires veterinary attention.

In most cases, black pigmentation on a cat’s gums is not painful and simply results in a dark discoloration of the gum tissue. Breeds with pigmented skin and gums, like the Bombay, Oriental Shorthair, and Siamese, often develop dark spots naturally as they age. Other causes like lentigo, melanoma, and chemical staining also lead to discoloration but don’t cause discomfort.

However, severely inflamed, swollen, or bleeding gums with a black/brown color can suggest gum disease like gingivitis. This can be quite painful and lead to tooth loss and systemic illness if left untreated. Trauma, cancer, or other mouth infections may also require medical care if accompanied by black gums. Overall, while discolored gums alone may not indicate disease, it’s still wise to have your veterinarian inspect any significant gum changes to diagnose or rule out underlying conditions (Cat Bandit, 2023).

Diagnosing the Cause of Black Gums

There are several diagnostic tests vets may perform to determine the underlying cause of black gums in cats:

  • Complete oral exam – The vet will perform a thorough visual inspection of the teeth, gums, mouth, and throat looking for signs of infection, inflammation, masses, or other abnormalities.
  • Radiographs (x-rays) – Dental x-rays allow vets to see below the gumline for signs of infection, tooth root problems, or masses not visible on the surface.
  • Biopsy – Taking a small tissue sample of the blackened gums and examining it under a microscope can help identify cancerous growths or other abnormalities.
  • Blood tests – Testing blood can reveal issues like anemia, infections, or other systemic illnesses contributing to gum discoloration.
  • Bacterial culture – Swabbing the gums and testing for pathogenic bacteria can identify a bacterial infection as the cause.

In addition to tests, the vet will thoroughly review the cat’s medical history and look for any other clinical signs that may point to the cause of black gums. The timing of when discoloration first occurred can also help narrow down the diagnosis. With a complete diagnostic workup, vets can determine the underlying issue and best course of treatment.

Treatment Options

If a cat has black gums due to an underlying medical condition, the treatment will focus on addressing the root cause.

For example, if gum disease is causing the discoloration, the vet may prescribe antibiotics or anti-inflammatory medication to fight infection and reduce inflammation. They may also recommend a deep dental cleaning to remove plaque and tartar from under the gumline (Source).

In cases of lentigo or melanosis, there is often no treatment needed if it is simply harmless pigmentation. However, the vet will want to rule out other causes first. They may recommend periodic monitoring to ensure no concerning changes develop (Source).

For cancerous growths, treatment may involve surgery, chemotherapy, or radiation. The prognosis depends on the type, size, and location of the tumor (Source).

The outlook is generally good if the black gums are simply due to normal pigmentation. No treatment is needed in those cases. However, it’s important to have regular veterinary checkups to monitor oral health.


There are several preventative measures cat owners can take to help keep their cat’s gums healthy and reduce the risk of black gums developing:

Regular dental cleanings and exams by a veterinarian are important. Veterinarians will scale plaque and tartar off the teeth and clean under the gumline. This helps prevent periodontal disease which can lead to black gums (Source).

Brushing your cat’s teeth at home can remove plaque before it turns into tartar. Use a soft bristled brush and cat-safe toothpaste. Brushing just a few times a week can make a big difference in gum health.

Dental diets and treats are available that are formulated to reduce plaque buildup. Chew toys and interactive feeders can also help scrape plaque off teeth.

Checking your cat’s gums and teeth regularly at home allows you to monitor for any problems. Look for redness, swelling, foul breath, and plaque buildup. Report any abnormalities to the vet.

Diet and Lifestyle Changes

Certain diet and environmental changes can help support gum health in cats with black gums.

Wet canned food is generally recommended over dry kibble for cats with gum issues like stomatitis. Canned foods have higher moisture content which can help reduce plaque buildup. According to this source, canned foods with high-quality protein sources like chicken, turkey, duck or rabbit are ideal.

Avoid hard kibble and treats as they can exacerbate dental problems. Soft treats or freeze dried options are gentler alternatives. Making meals moist by adding warm water can also make kibble easier to chew and digest.

Ensure fresh, clean water is always available to promote hydration and oral health. Place multiple bowls around the home. Consider getting a cat water fountain to encourage drinking.

Minimize stress for your cat which can worsen gum inflammation. Provide a calm environment, hiding spots, high perches, and affection. Reduce noisy appliances, children or pets interacting roughly, and new people.

Regular grooming and tooth brushing can prevent plaque buildup. Introduce brushing slowly with pet-safe toothpaste. Seek guidance from your veterinarian.

Home Care Tips

There are some things you can do at home to help care for your cat’s gum health:

Brush your cat’s teeth regularly to remove plaque buildup. Use a soft-bristled brush and cat-safe toothpaste. This can help prevent tartar accumulation and keep gums healthy.

Check your cat’s gums and teeth regularly for any abnormalities. Healthy gums should be pink, not red, swollen or bleeding. If you notice any concerning signs, take your cat to the vet.

Switch to wet food or add water to dry food to encourage chewing. This helps dislodge food particles stuck in the teeth.

Provide safe chew toys to help scrape plaque off teeth. Look for toys made of rubber or rope.

Consider dental treats or foods formulated to reduce tartar. These may help if brushing is difficult.

Schedule regular dental cleanings with your vet to prevent advanced gum disease.

See your vet promptly if you notice bleeding gums, gum swelling, foul breath, loose teeth or other problems. These require medical treatment.


The prognosis for black gums in cats can vary greatly depending on the underlying cause. In many cases, black pigmentation on the gums is benign and requires no treatment. This pigmentation is simply a normal variant in some cats, especially in breeds with orange, gray, or light-colored coats. For benign pigmentation, the prognosis is excellent.

However, black gums can also be a sign of more serious conditions like melanoma, squamous cell carcinoma, or other oral cancers. With oral cancer, the prognosis depends on the type, location, and stage of the cancer. According to one source, the median survival time for cats with squamous cell carcinoma affecting the gums is about 2-4 months without treatment.

Aggressive surgical removal, radiation therapy, chemotherapy or immunotherapy may prolong survival times but prognosis with feline oral cancer is generally guarded to poor. Early recognition and treatment offer the best chances for improved prognosis.

For other causes of black gums like gum disease, the prognosis is good if the condition is addressed early with proper dental care and treatment. Left untreated, severe gum disease can lead to tooth loss and infections which may impact overall health.

In summary, while black gums are common and often benign in cats, any abnormalities should be evaluated by a veterinarian to determine the underlying cause and recommend appropriate treatment if needed.

Warning Signs

There are several concerning signs to watch for if your cat has black gums:

  • Swelling or inflammation in the gums
  • Bleeding from the gums
  • Redness around the gums
  • Bad breath or foul odor from the mouth
  • Excessive drooling
  • Difficulty eating or loss of appetite
  • Visible tartar or plaque buildup on teeth
  • Loose or lost teeth
  • Pawing at the mouth
  • Decreased energy or lethargy

You should seek emergency veterinary care if your cat is drooling excessively, has bleeding from the gums, is in apparent pain, or is unwilling or unable to eat. These can be signs of a serious oral health issue requiring urgent treatment. Don’t hesitate to call your vet or visit an emergency animal hospital if your cat displays any of these alarming symptoms along with black gums.

Some sources of information on warning signs in cats with black gums:



When to See the Vet

If your cat has black gums, it is recommended to schedule a veterinary dental checkup regularly, even if no issues are apparent. Your vet can closely examine your cat’s mouth and identify any underlying causes that may need treatment. According to the American Veterinary Medical Association, annual veterinary dental cleanings and exams help prevent periodontal disease in cats.

See your vet right away if your notice any of the following signs in your cat (Quora):

  • Inflamed, bleeding, or receding gums
  • Bad breath or mouth odor
  • Excessive drooling
  • Loss of appetite
  • Difficulty eating or chewing
  • Pawing at their mouth

While black gums can sometimes be harmless pigmentation, any changes in gum color or dental issues need professional veterinary attention. It’s always better to be safe than sorry when it comes to your cat’s health. Don’t delay – schedule a vet visit promptly if you have any concerns about your cat’s oral health.

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