Cats on the Tongue. The Risks of Letting Your Cat Lick the Inside of Your Mouth


Getting an unexpected lick on the mouth from your feline companion can be a surprising experience. While many cat owners may think it’s cute, is it actually safe to allow this kind of close contact? In this article, we’ll explore what can happen if a cat’s tongue enters your mouth and the potential health implications.

Cats regularly use their tongues for grooming and other functions. A cat’s tongue isn’t just a scratchy piece of fabric – it can harbor bacteria, viruses, and parasites. Some of these organisms may be harmless to your cat but could potentially make you sick if they get into your mouth. Your risk depends on factors like your own health status and what pathogens your cat may have been exposed to.

We’ll cover the main infections you could get from a feline lick to the mouth. You’ll also learn who is most vulnerable, how to prevent transmission, and when you may need medical care. While it’s generally harmless for a cat to briefly lick your lips, certain precautions are advised if they persistently try to lick the inside of your mouth.

Risk of Infection

Cat saliva contains bacteria that can cause disease in humans if transmitted through a bite, scratch, or lick. Some of the bacteria found in cat saliva include Capnocytophaga, Bartonella henselae, and Pasteurella multocida.

While rare, diseases that can be transmitted from cats to humans through saliva include cat scratch disease, sepsis, and bacterial infections. Transmission occurs most often through bites and scratches that break the skin, allowing bacteria to enter. Licking broken skin or mucous membranes, like the mouth, can also lead to infection.

Cats groom themselves frequently, so bacteria can accumulate in their mouths even if they appear healthy. Kittens tend to bite and scratch more during play, so they may pose a higher risk of transmitting bacteria through saliva until they are older.

Common Bacterial Infections

There are several types of bacterial infections that cats can spread to humans through licking and bites. Some of the most common include:

Bartonellosis (Cat Scratch Fever)

Bartonellosis, also known as cat scratch fever, is caused by the bacteria Bartonella henselae. Cats are the main reservoir for Bartonella henselae and symptoms in humans usually occur within 3-14 days after a bite or scratch. In rare cases, the bacteria can also be transmitted through a cat licking an open wound. Symptoms include fever, headache, fatigue, and swollen lymph nodes near the scratch or bite. While most cases are mild, bartonellosis can lead to more serious complications like encephalitis in immunocompromised individuals. Antibiotics are used to treat bartonellosis [1].


Pasteurellosis is caused by the bacteria Pasteurella multocida which commonly lives in a cat’s mouth and upper respiratory tract. Bites are the most common route of transmission to humans, but Pasteurella can also be spread through licking. Symptoms usually start within 24 hours and include redness, pain, and swelling at the site of the bite or lick. More severe complications like joint infections or blood poisoning are possible but rare. Antibiotics can successfully treat pasteurellosis [2].

Capnocytophaga canimorsus

Capnocytophaga canimorsus is a bacteria found in cat and dog mouths that can be transmitted through bites, licks, or close contact. Infections are rare but can be severe or even life-threatening. People with weakened immune systems are at highest risk. Symptoms appear within 1-14 days and include fever, vomiting, diarrhea, headaches, confusion, and muscle pain. More serious complications like septic shock, organ failure, or gangrene can occur. Aggressive antibiotic treatment is required, and in some cases surgery to remove infected tissue [3].

Common Viral Infections

Some viruses can be transmitted from cats to humans through bites and scratches. Three of the most concerning viral infections are:


Rabies is a deadly viral disease that affects the central nervous system. It is spread through the saliva of infected animals. If a rabid cat bites or scratches hard enough to break the skin, the virus can enter the wound and infect the human. Rabies has a nearly 100% fatality rate once symptoms appear. However, the rabies vaccine is highly effective in preventing the disease if administered promptly after exposure. [1]

Feline Immunodeficiency Virus

Feline immunodeficiency virus (FIV) weakens a cat’s immune system in a manner similar to HIV in humans. It is primarily spread through bite wounds between cats. Cases of humans contracting FIV from cats are very rare. However, immunocompromised individuals should take precautions around FIV-positive cats. [2]

Feline Leukemia Virus

Feline leukemia virus (FeLV) suppresses the cat’s immune system and increases susceptibility to other diseases. It spreads between cats through saliva, nasal secretions, urine, feces, and milk. Bites are the most efficient mode of transmission. There are only a few documented cases of humans becoming infected with FeLV. However, immunocompromised people should exercise caution around infected cats. [3]

Parasitic Infections

When a cat’s saliva comes into contact with broken skin or mucous membranes like the mouth, nose, or eyes, parasitic infections can be transmitted. One of the most concerning parasites is Toxoplasma gondii, the parasite that causes toxoplasmosis.

Toxoplasma infection occurs when the parasite enters the body. According to the CDC, cats get Toxoplasma infection by eating infected rodents, birds or other small animals, or anything contaminated with feces from another cat that is shedding the parasite. The parasite then multiplies in the cat’s intestine and is shed in the feces for one to three weeks. The parasite becomes infectious one to five days after being shed. Humans can become infected by ingesting contaminated food or water or by accidentally ingesting infected cat feces by touching their hands to their mouth.

Once a human is infected with toxoplasmosis, the parasite can remain dormant in the body for years. For those with weakened immune systems, reactivation can occur leading to severe complications. Toxoplasmosis infection in healthy adults often causes no symptoms. When symptoms do occur, they are usually mild and similar to the flu. Symptoms may include swollen lymph nodes, muscle aches, and fever. In severe cases, toxoplasmosis can cause damage to the brain and eyes. For pregnant women, infection can lead to miscarriage, premature delivery, and severe illness in newborns according to the Mayo Clinic.

Other parasites that can be transmitted through a cat’s saliva include roundworms and hookworms. Roundworms live in a cat’s intestine and eggs are shed in the feces. Humans can accidentally ingest eggs that have contaminated soil, food, or water. Hookworms attach to the intestinal wall and release eggs into a cat’s feces. If larvae penetrate human skin, they can migrate through the body causing cutaneous larva migrans.

Who is Most at Risk?

Certain populations are at higher risk of illness if a cat licks them in the mouth.

People with weakened immune systems, such as those with HIV/AIDS, cancer, or autoimmune disorders, are at increased risk. Their compromised immune systems have a harder time fighting off infections transmitted via cat saliva (CDC, 2022).

Young children are also at elevated risk. Their immune systems are still developing, leaving them more susceptible to bacterial and parasitic infections. Children under 5 years old often exhibit hand-to-mouth behaviors, so if they’ve touched a cat and put their hands in their mouth, they may ingest bacteria or parasites (CDC, 2022).

Elderly individuals, especially those over 65 years old, have natural immune system decline due to aging. Their bodies have a tougher time fending off transmissible illnesses. Bacteria like Capnocytophaga can more easily overwhelm their defenses (Healio, 2018).

In general, those with weakened immunity due to health conditions or age extremes are most vulnerable to infections from cat saliva exposure. Proper precautions should be taken with these high-risk groups.

Preventing Transmission

Cats may carry various diseases that can be transmitted to humans. However, there are ways you can prevent transmission when interacting with cats. The most important is to avoid mouth contact with cats:

  • Cats groom themselves using their tongues, spreading their saliva all over their fur. A cat’s saliva can contain bacteria, viruses, and parasites that may cause disease in humans if they enter the mouth or are swallowed.
  • Allowing cats to lick your mouth or face, or placing your mouth on a cat directly, provides a route for disease transmission to occur. Do not let cats lick the inside of your mouth or nose.

It is also important to wash your hands with soap and warm water after petting or handling cats. Their saliva, feces, and urine can contaminate your hands, leading to accidental swallowing of microbes if you touch your face or eat without washing up first.

Additionally, keeping cats indoors reduces their exposure to infectious agents outdoors, lessening their likelihood of carrying transmissible diseases. Outdoor cats have more opportunities for contact with wildlife, stray cats or their excretions, and contaminated environments. Indoor cats pose less of a disease risk to humans than outdoor-roaming cats.

According to Cornell University College of Veterinary Medicine, basic hygiene can prevent the spread of diseases from cats to humans.

Signs of Infection

If a person develops an infection after being licked in the mouth by a cat, they may experience a variety of symptoms. Some of the most common signs of infection include:

Flu-like symptoms: Infections like cat scratch disease can cause flu-like symptoms such as fever, headache, fatigue, loss of appetite, and muscle aches. The fever may come and go.

Swelling/redness at wound site: At the location where the cat’s tongue made contact with the skin, such as on the lips or inside of the mouth, redness, pain, and swelling can develop. This is a sign the area has become infected.

Fever: One of the hallmark symptoms of infections transmitted by cats is a fever, which is a body temperature above 100.4°F (38°C). The fever may be mild or high depending on the type of infection.

Other symptoms may include a rash or pustules on the skin, swollen lymph nodes near the original wound, sore throat, and muscle pains. In some cases, symptoms can be severe and require prompt medical treatment, especially for those with weakened immune systems.

When to See a Doctor

If you or your child develops concerning symptoms after a cat licks the mouth or face, it’s important to seek medical care. Here are some key signs that warrant a doctor visit:

  • Persistent symptoms: If symptoms like fever, sore throat, or swollen lymph nodes last more than a few days, see a doctor. Prolonged symptoms can signal an infection.

  • Difficulty breathing: Labored or rapid breathing after contact with a cat requires urgent medical care, as it may indicate a serious infection.

  • High fever: Temperatures over 101°F in children, or over 103°F in adults, merit medical evaluation after cat contact. Fevers this high can be a sign of infection.

Don’t hesitate to call your doctor if you have any lingering concerns following a cat licking your mouth. It’s better to be safe when it comes to potential infections.


In summary, there are some risks associated with a cat licking the inside of your mouth, but they are generally low for most healthy adults. The main risks are bacterial infections like cat scratch disease and pasteurellosis, viral infections like rabies, and parasitic infections like toxoplasmosis. People with weakened immune systems, like the elderly, pregnant women, and young children are at higher risk of developing an infection.

To prevent transmission, avoid allowing cats to lick the inside of your mouth, wash any saliva off your skin promptly, and don’t share food or dishes with cats. Seek medical attention if you develop any signs of infection like fever, muscle aches, headache, or swollen lymph nodes after a cat licks the inside of your mouth. But for most healthy individuals, while allowing open mouth licking is not advised, the risks are minimal if it occurs occasionally.

The key takeaway is to take sensible precautions, but not to be unduly alarmed by an isolated incident of a cat licking inside your mouth, as the chances of infection are quite low in healthy people.

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