Feline Friends or Foes? How Cats Can Wreak Havoc on Your Tummy


Our furry feline friends can bring joy and comfort into our lives. However, some studies suggest that cat ownership may have an unexpected downside – increased risk of stomach problems in humans.

One survey found that 13% of cat owners reported frequent vomiting or diarrhea, compared to only 9% of non-cat owners (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2870492/). While correlation does not equal causation, researchers speculate that exposure to cat-related parasites, bacteria, and allergens may irritate the human digestive tract.

In this article, we’ll explore the possible links between cats and human stomach issues, including common culprits like toxoplasmosis and cat scratch disease. We’ll also provide tips to reduce your risk while still enjoying time with the cats you love.

Common Cat-Related Stomach Issues

Cats can sometimes transmit diseases or parasites to humans that cause stomach problems. Some of the most common cat-related stomach issues in people include:


Toxoplasmosis is an infection caused by the Toxoplasma gondii parasite. Cats are the definitive host for T. gondii, which means the parasite can only sexually reproduce in cats. The parasite is shed in cat feces, and humans can contract toxoplasmosis by accidentally ingesting infected feces, such as through contaminated food or contact with cat litter. [CDC]

In humans, toxoplasmosis often causes no symptoms, but when present, symptoms may include fever, muscle pain, headache, sore throat, or fatigue. Some people develop swollen lymph nodes or vision problems. In rare cases, toxoplasmosis can cause serious complications such as lung, heart or brain problems. People with weakened immune systems are at highest risk of severe infection.

Cat Scratch Disease

Cat scratch disease (CSD) is an infection caused by the bacterium Bartonella henselae, which cats may carry in their blood. Humans can contract CSD through a bite or scratch from an infected cat. Symptoms of CSD can include swollen lymph nodes, fever, fatigue, and loss of appetite. In some cases, more serious complications may occur such as skin lesions, liver and spleen enlargement, or damage to the eyes, heart or brain. [CDC]

Cat Allergies

Allergies to cats are common and can cause digestive symptoms in some people. Cat allergens are found in their saliva, skin dander, and urine. Symptoms of a cat allergy may include digestive issues like nausea, vomiting, diarrhea, and abdominal pain. Some people may also experience hives, congestion, or wheezing when exposed to cats. Cat allergies are caused by an overreaction of the immune system to otherwise harmless cat proteins. [American College of Allergy, Asthma & Immunology]

Toxoplasmosis Explained

Toxoplasmosis is an infection caused by the Toxoplasma gondii parasite. This parasite is found in cat feces and spreads through contact with infected cat feces, often when cleaning the litter box (https://www.cdc.gov/parasites/toxoplasmosis/gen_info/faqs.html). The Toxoplasma gondii parasite can also be found in undercooked meat and contaminated water.

When humans are infected with toxoplasmosis, the most common symptoms are swollen lymph nodes and muscle aches and pains that may resemble the flu. In more severe cases, toxoplasmosis can cause blurred vision, confusion, loss of coordination, and seizures (https://www.mayoclinic.org/diseases-conditions/toxoplasmosis/symptoms-causes/syc-20356249). However, many people infected with toxoplasmosis never develop signs or symptoms at all.

For pregnant women, toxoplasmosis can cause severe symptoms if transmitted to the fetus, including eye and brain damage. But precautions can be taken to avoid toxoplasmosis infection during pregnancy, such as avoiding changing cat litter boxes.

Cat Scratch Disease Overview

Cat scratch disease (CSD) is caused by the Bartonella henselae bacteria which can be transmitted to humans through scratches, bites, or licks from infected cats, especially kittens. The disease often causes swollen lymph nodes and fever within 3-14 days after exposure. Other common symptoms include fatigue, headache, poor appetite, and abdominal pain in the upper right quadrant where the liver is located.

According to research, abdominal pain occurs in 20-46% of CSD cases, likely due to granulomatous inflammation affecting organs like the liver and spleen. One study found that 64% of patients with hepatosplenic CSD complained of abdominal pain [1]. Enlargement of the liver and spleen (hepatosplenomegaly) is observed in 5-20% of patients [2] and can cause nausea, vomiting, and abdominal discomfort.

Cat Allergy Symptoms

One of the most common allergic reactions to cats is caused by the Fel d 1 protein found in cat saliva, skin, and fur. When humans are exposed to this protein, it can trigger an IgE-mediated allergic response in those who are susceptible. Common symptoms of cat allergies include:

Gastrointestinal issues: Some people may experience nausea, vomiting, diarrhea, and abdominal pain after exposure to cats or cat dander. According to studies, around 10-15% of people with cat allergies develop gastrointestinal symptoms. The exact mechanism is not fully understood but is likely related to ingestion or inhalation of the Fel d 1 allergen.1

Respiratory issues: Cat allergies commonly cause sneezing, coughing, respiratory congestion, runny nose, and asthma attacks in susceptible individuals. This is caused by inhaling cat dander that contains Fel d 1 particles.2

Skin reactions: Some people may develop rashes, hives, eczema flares, and itchy skin after contact with cats. The allergen binds to mast cells in the skin, triggering histamine release and inflammation.

Eye symptoms: Itchy, watery, red eyes are also common in cat-allergic patients. This is caused by exposure of the eyes to airborne cat allergens.

Anaphylaxis: While rare, anaphylactic shock can occur in highly sensitized individuals after cat allergen exposure.

Treatment involves allergen avoidance, medications, and immunotherapy. Keeping the cat out of bedrooms, using HEPA filters, washing hands after contact, and vacuuming frequently may help reduce allergen levels. Antihistamines, nasal steroids, bronchodilators, and emergency epinephrine can relieve acute symptoms. Allergy shots are also an effective way to desensitize the immune system over time.

Preventing Transmission

There are a few key ways to help prevent the transmission of cat-related stomach issues to humans:

Proper hand hygiene is crucial. Be sure to wash hands thoroughly with soap and warm water after handling cat litter, cleaning the litter box, or touching cat feces. Scrub hands for at least 20 seconds. Hand sanitizer can be used as an additional precaution.

Avoid exposure to cat feces as much as possible. Use gloves and scoop litter boxes daily to reduce exposure. Disinfect any surfaces contaminated by feces using diluted bleach.

According to the CDC, keeping cats indoors can reduce the risk of disease transmission. Indoor cats have less exposure to parasites and infected rodents that can transmit toxoplasmosis and other diseases. Cats should be kept indoors or supervised when outdoors.

Additionally, pregnant women should avoid changing litter boxes to prevent toxoplasmosis exposure. Have someone else perform this task instead.

Diagnosis and Treatment

Diagnosing parasite or bacterial infections in cats typically involves a combination of medical history, physical exam, bloodwork, and diagnostic imaging. Some common diagnostic tests include:

Toxoplasmosis diagnosis may involve testing blood, body fluids, or tissue samples for the presence of Toxoplasma antibodies or DNA (https://bondvet.com/b/cat-digestive-problems). Imaging tests like X-rays, ultrasound, or CT scans can check for signs of infection.

Diagnosing cat scratch disease relies on clinical signs and testing lymph node aspirates or biopsy samples for Bartonella bacteria (https://www.merckvetmanual.com/cat-owners/digestive-disorders-of-cats/disorders-of-the-stomach-and-intestines-in-cats). Blood tests may reveal elevated white blood cell count.

Treatment generally involves medications like antibiotics, antiprotozoals, corticosteroids, or pain relievers. Antibiotics like Doxycycline are commonly used for cat scratch disease and toxoplasmosis. Other medications may include Clindamycin, Sulfadiazine, or Pyrimethamine. Treatment duration depends on the infection severity and response to medication.

When to See a Doctor

You should take your cat to the veterinarian if they have any of the following symptoms:

  • Persistent diarrhea lasting more than 24 hours
  • Frequent vomiting over a 12-24 hour period
  • Severe abdominal pain indicated by crying, stretching, or tense abdomen
  • Fever over 103°F

Diarrhea and vomiting can lead to dehydration which can be dangerous if left untreated. Severe abdominal pain and fever may be signs of a serious condition requiring medical attention such as pancreatitis, inflammatory bowel disease, intestinal obstructions, or cancer.

It’s important not to wait too long to seek veterinary care if your cat has these symptoms. Catching and treating the underlying condition early can help prevent complications and relieve your cat’s discomfort.

Managing Cat Allergies

If you are allergic to cats but don’t want to part with your feline friend, there are some steps you can take to manage your allergies:

Keep cats out of bedrooms – One of the most important things you can do is keep cats out of your bedroom as much as possible (WebMD). The bedroom should be a cat-free zone, since you spend many hours sleeping there. Shutting cats out of the bedroom prevents continued allergen exposure throughout the night.

Use HEPA filters – High efficiency particulate air (HEPA) filters can help remove allergens like cat dander from the air (OSU). Use standalone HEPA filters in bedrooms or other rooms the cat frequents. Make sure any vacuum you use is equipped with a HEPA filter too.

Consider hypoallergenic cats – Some cat breeds produce less Fel D1 protein, the major cat allergen. Breeds like the Siberian, Russian Blue, and Bengal may be better tolerated by allergy sufferers (WebMD). But remember that there are no truly non-allergenic cats.


In summary, while cats can transmit some stomach issues to humans, the overall risk is relatively low for healthy individuals. The main cat-related stomach problems include toxoplasmosis, cat scratch disease, and cat allergies. Toxoplasmosis is usually asymptomatic but can cause flu-like symptoms or be dangerous during pregnancy. Cat scratch disease results in swollen lymph nodes and fever after a cat scratch or bite. Cat allergies manifest as digestive issues like vomiting, diarrhea, and abdominal pain in sensitive individuals. Practicing good hygiene like washing hands after contact can prevent transmission in many cases. If symptoms develop after exposure to a cat, see a doctor for proper diagnosis and treatment, which may include medication or dietary changes. For cat owners, measures like keeping cats indoors, proper litter box maintenance, and regular vet visits can reduce risk. Overall, simple precautions can allow cat lovers to enjoy their pets while avoiding potential stomach problems.

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