Secondhand Smoke. Is Your Dog at Risk?


Passive smoking, also known as secondhand or environmental tobacco smoke, refers to the inhalation of tobacco smoke by non-smokers who are in proximity to active smokers. Just like humans, when dogs breathe in secondhand smoke it can have negative impacts on their health. Studies have shown that dogs living in smoking households have a higher risk of developing cancer, respiratory issues, and heart disease compared to dogs in smoke-free homes.

This article explores the question – can dogs be passive smokers? We will look at the health consequences of secondhand smoke exposure in dogs, including cancer, breathing problems, heart disease and other issues. The signs of a dog suffering from the effects of passive smoking will also be covered. By the end, dog owners will understand the potential risks and learn how to protect their pets from environmental tobacco smoke.

Do Dogs Breathe In Secondhand Smoke?

Dogs have respiratory systems that function very similarly to humans. When they breathe in air, it travels down their trachea and into their lungs. The lungs contain tiny air sacs called alveoli that allow oxygen to enter the bloodstream and carbon dioxide to exit the body. This is the same process that happens in human lungs.

dog breathing in secondhand smoke

Because dogs’ respiratory systems work like ours, dogs inhale any airborne particles and chemicals when they breathe. Smoke particles from cigarettes, cigars, pipes, or cannabis diffuse into the air that surrounds the smoker. Dogs in the vicinity have no choice but to breathe in this contaminated air, taking the smoke deep into their lungs. According to veterinarians, dogs passively inhale secondhand smoke anytime they are near someone smoking tobacco or cannabis products (source).

In summary, dogs cannot avoid breathing in secondhand smoke since their lungs take in whatever is present in the surrounding air, just like human lungs. When cigarette, cigar, pipe, or cannabis smoke is in their environment, dogs inhale the hazardous chemicals and particles along with their normal breaths.

Health Risks From Secondhand Smoke

Secondhand smoke poses significant health risks in humans, including cancer, respiratory problems, and heart disease. Research shows that dogs exposed to tobacco smoke face many of the same risks as humans.

A study by the University of Glasgow found that dogs living with smokers were 4 times more likely to develop nasal cancer compared to dogs in smoke-free homes. The types of cancer were similar to those diagnosed in humans, including carcinoma and sarcoma [1].

Dogs can also develop respiratory conditions from secondhand smoke, like coughing, wheezing, and asthma. One reason is that dogs have increased mucus production from smoke irritation, partially obstructing their airways [2].

Lastly, research from Colorado State University found that dogs exposed to secondhand smoke had a 31% higher chance of developing lung cancer and a 25% higher chance of getting heart disease. Again, similar risks that affect humans [3].


dog with cancer from secondhand smoke

Dogs exposed to secondhand smoke are at an increased risk for certain types of cancer, especially lung cancer and nasal cancer. Studies show that dogs living with smokers have a 60% higher chance of getting lung cancer and a 2-4 times greater chance of getting nasal cancer compared to dogs not exposed to tobacco smoke.

According to the ASPCA, the two most common cancers seen in dogs exposed to secondhand smoke are:

  • Lung cancer – Dogs breathe in carcinogenic chemicals just like humans do. Tobacco smoke contains over 7,000 chemicals, 70 of which are known to cause cancer.
  • Nasal cancer – The long noses of dogs combined with their proximity to secondhand smoke puts them at high risk of nasal cancer. Studies show over 60% of dogs with nasal cancer lived in a home with a smoker.

Exposure to tobacco smoke, even occasionally or at low levels, increases the risk of lung and nasal tumors. One study found that dogs living with 1-2 smokers had lung cancer rates 4 times higher than average.[1]

Respiratory Problems

Secondhand smoke can cause significant respiratory problems in dogs. The harmful chemicals in cigarette smoke irritate the airways and lungs, leading to inflammation and increased risk of infections.

dog having respiratory illness

Studies show that dogs living in smoking households have a higher rate of respiratory issues than dogs in smoke-free homes. According to the Humane Society Veterinary Medical Association, dogs exposed to secondhand smoke are 3 times more likely to develop lung and nasal cancer and are 2.5 times more likely to have allergies and respiratory problems compared to dogs in non-smoking environments (The Effects of Secondhand Smoke on Pets).

Dogs with short snouts, like pugs and bulldogs, are especially susceptible since they naturally have narrowed airways. But all breeds are at risk. The harmful fumes can lead to chronic bronchitis, pneumonia, and other infections in dogs’ respiratory tract.

Protecting dogs from secondhand smoke by taking smoking outside or quitting altogether can prevent many respiratory illnesses in canine companions.

Heart Disease

Secondhand smoke can have a significant impact on heart health in dogs. Dogs exposed to tobacco smoke are at higher risk for developing heart disease and experiencing heart attacks.

A study by Tufts University found that dogs with chronic mitral valve disease who lived with smokers were three times more likely to die of a heart attack compared to dogs living in a smoke-free home [1]. The chemicals in cigarette smoke cause inflammation and damage to heart tissue and blood vessels. Over time, this leads to heart failure, arrhythmias, and heart attacks in dogs.

One study showed that nearly 30% of dogs exposed to tobacco smoke had moderate to severe heart disease, while only 6% of unexposed dogs had heart disease [2]. The carcinogens and toxins in cigarette smoke create oxidative stress that alters heart rhythm and function. Keeping dogs away from tobacco smoke is crucial for protecting their cardiovascular health.

Other Health Effects

Secondhand smoke can have a wide range of other negative health impacts on dogs beyond cancer, respiratory issues, and heart disease. According to the FDA, strokes are more common in dogs exposed to tobacco smoke, likely due to the cardiovascular effects of inhaled smoke [1]. Allergies also appear more frequently in dogs living with smokers, as the smoke irritates their respiratory tracts and sinuses. Obesity is another concern, as carcinogens and nicotine can disrupt dogs’ metabolisms and hormone regulation.

Most troubling is the significantly shortened lifespan of dogs regularly exposed to tobacco smoke. According to the FDA, dogs living in a smoking household live on average 1.5 – 2.5 years less than dogs in a smoke-free home, largely due to elevated cancer risks [2]. Removing dogs from secondhand smoke exposure can help mitigate these risks and extend their healthy years.

Protecting Your Dog From Secondhand Smoke

The best way to protect your dog from the dangers of secondhand smoke is to keep your home and car completely smoke-free. According to the FDA, smoking indoors can deposit toxic particulates everywhere – on floors, furniture, drapes, and other surfaces where they can linger (FDA). These toxins can stick to your dog’s fur and be ingested when grooming. Making your home and vehicle 100% smoke-free spaces ensures your dog won’t be breathing in any secondhand smoke.

It’s also important not to smoke near your dog even when outdoors. Smoke can blow towards your dog and get trapped in their fur. One study found higher levels of nicotine on the hair of dogs belonging to smokers vs non-smokers (Tobacco Free Life). So if you do smoke, do so away from your pet.

Lastly, monitor your dog closely for any signs of respiratory distress or illness that could indicate health effects from secondhand smoke exposure. Take them to the vet promptly if you notice coughing, wheezing, eye discharge, or lethargy. Getting timely treatment for any smoke-related health issues will give your dog the best chance of recovery.

Signs Your Dog Is Suffering From Secondhand Smoke

There are several signs that indicate your dog may be suffering health effects from inhaling secondhand smoke:

signs of dog suffering from secondhand smoke


As we’ve seen, secondhand smoke poses serious health risks for dogs, just as it does for humans. Dogs exposed to tobacco smoke are more likely to develop cancer, respiratory illnesses, and heart disease. Even short-term exposure can irritate their lungs and airways.

It’s absolutely crucial for dog owners who smoke to take steps to protect their pets. The best option is to quit smoking altogether with the help of your doctor or a smoking cessation program. But even cutting back on smoking around your dog and ensuring good ventilation can make a big difference.

Protecting your dog’s health should be a top priority. They rely on us to keep them safe. With some simple lifestyle changes, you can dramatically reduce your pet’s exposure to harmful secondhand smoke. There are many resources available to help you quit, so you and your dog can enjoy better health.

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