Home » Pet Health » Toxins and Your Pet » Smoke Exposure and Risk of Cancer in Pets


Exposure to smoke produced from burning tobacco products such as cigarettes, cigars, or pipes can affect your pet’s health. Tobacco smoke is rich in harmful chemicals and toxic gases such as tar, carbon monoxide, and hydrogen cyanide, as described below:

    • Tar – a substance that damages the lungs by narrowing the tiny air tubes (bronchioles) that absorb oxygen, possibly leading to lung cancer.
    • Carbon monoxide – a toxic gas that can significantly decrease oxygen levels in the blood, possibly leading to heart disease and stroke.
    • Hydrogen cyanide – a highly poisonous gas that prevents cells from using oxygen.

Additional cancer-causing chemicals in tobacco smoke include formaldehyde, arsenic, and benzene. If your pet experiences second-hand or third-hand smoke, they may be exposed to these harmful substances, thus putting their health at risk.

What are second-hand and third-hand smoke?

First-hand smoke refers to the tobacco smoke inhaled by a smoker. Second-hand smoke is the smoke that pets unintentionally breathe in. Third-hand exposure occurs when chemical residues from smoke stick to household items such as clothes, furniture, rugs, carpets, and other materials. A pet may unintentionally become exposed to these harmful chemical residues simply by physical contact.

Short-term exposure to smoke can impact how the immune system in the lungs works, leading to breathing problems ranging from minor coughing to asthma. Pets exposed to second-hand and third-hand smoke may also suffer from bronchitis and pneumonia. Long-term exposure may lead to different kinds of cancers in pets.

How does smoke exposure increase cancer risk in pets?

There are several ways your pet’s health may be at risk due to smoke exposure. In cats, persistent second-hand smoke exposure poses a risk of lung cancer and can also lead to an increased incidence of blood cancer lymphomas in cats. Third-hand smoke exposure, where your cat repetitively licks smoke-based carcinogenic contents from fur, furniture, and clothes, may lead to oral cancer.

Dogs subjected to smoke constantly have an increased chance of developing nasal cancer. Additionally, researchers have reported that dogs with longer noses have a higher incidence of nasal cancer because of the physical and biological differences from short-nosed dogs. An association between second-hand smoke and lung cancer in dogs is still in question.

How do you practice prevention?

To protect the health of your beloved pet, you want to keep them away from second-hand and third-hand smoke. If you’d like to reduce your pet’s smoke exposure, you can consider the following:

    • Keep all tobacco products out of your pet’s reach
    • Only smoke outdoors
    • Wash your hands after smoking
    • Change your clothes after smoking
    • Keep ashtrays clean
    • Dispose of all cigars, cigarettes, nicotine gums, patches, snuff, and other products in a pet-proof container

Arming yourself with the knowledge of how smoke can affect your pet and taking the necessary steps to prevent exposure are great ways to protect your pet from the potentially harmful effects of smoking. You can also speak to your vet about treatments if you suspect your pet is ill due to contact with smoke-related substances.

The Pet Cancer Foundation’s Website Editorial team is comprised of veterinarians, veterinary oncologists, and veterinary technicians, as well as scientific writers and editors who have attained their PhD’s in the life sciences, along with general editors and research assistants. All content found in this section goes through an extensive process with multiple review stages, to ensure this extended resource provides pet families with the most up-to-date information publicly available.

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Last Updated: July 20, 2022

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The following sources were referenced to write the content on this page:

Bertone, ER, Snyder, LA & Moore, AS 2002, ‘Environmental tobacco smoke and risk of malignant lymphoma in pet cats’, Am J Epidemiol, vol. 156, no. 3, pp. 268-273.

Cannon, CM 2015, ‘Cats, cancer and comparative oncology’, Vet Sci, vol. 2, no. 3, pp. 111-126.

Pérez, N, Berrío, A, Jaramillo, JE, Urrego, R & Arias MP 2014, ‘Exposure to cigarette smoke causes DNA damage in oropharyngeal tissue in dogs’, Mutat Res Genet Toxicol Environ Mutagen, vol.769, pp.13-19.

Reif, JS, Bruns, C & Lower, KS 1998, ‘Cancer of the nasal cavity and paranasal sinuses and exposure to environmental tobacco smoke in pet dogs’, Am J Epidemiol, vol. 147, no. 5, pp. 488-492.

Roza, MR & Viegas, CA 2007, ‘The dog as a passive smoker: effects of exposure to environmental cigarette smoke on domestic dogs’, Nicotine Tob Res, vol. 9, no. 11, pp. 1171-1176.

Zierenberg-Ripoll, A, Pollard, RE, Stewart, SL, Allstadt, SD, Barrett, LE, Gillem, JM & Skorupski, KA 2018, ‘Association between environmental factors including second-hand smoke and primary lung cancer in dogs’, J Small Anim Pract, vol. 59, no. 6, pp. 343-349.

The Pet Cancer Foundation’s medical resource for pet owners is protected by copyright.

For reprint requests, please see our Content Usage Policy.