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Dog and secondhand smoke from cigarette

Effects of second-hand smoke on pets

We know that smoking poses health risks to people, but what about to the pets who share our homes? For more than two decades researchers have studied the effects of secondhand smoke on household pets and have found that our furry friends share many of the same risks from exposure to tobacco smoke. Since our pets spend nearly all their time in the home, they are exposed to any smoking-related toxins for extended periods.

Second-hand Smoke and Dogs

The lung structure of both dogs and cats is quite similar to that of humans. Exposure to second-hand tobacco smoke can cause allergic reactions, inflammation and nasal or pulmonary cancers in both dogs and cats. Interestingly, muzzle length seems to play a role in the risk and types of cancer experienced by dogs who live with smokers. Dogs with longer muzzles have an increased risk for nasal cancers, because of the increased surface area of nasal membrane where toxins can accumulate. Short-muzzled dogs, however, have an increased risk for lung cancer. Dogs are also more likely to be exposed to tobacco’s carcinogens through chewing on or accidentally ingesting discarded cigars, cigarettes, filters, or cigarillo tips.

Second-hand Smoke and Cats

Cats are more likely to develop oral or lymphatic cancers as a result of living with an owner who smokes. Because they groom themselves by licking their fur, they are likely to ingest any toxins that gather there. Lymphomas are a leading cause of death in cats, and a 2002 study in the American Journal of Epidemiology has shown that a threefold increase in the risk for lymphomas exists among cats who live with smokers. Cats are also at greater risk for respiratory infections and allergic reactions when exposed to nicotine smoke. Cats are also at greater risk for oral cancers (such as feline squamous cell carcinoma) when living with owners who smoke.

Vaping and Pets

Recently the popularity of e-cigarettes (or vaping—the smoking of flavored, nicotinized water vapor) has presented smokers with a “cleaner” alternative to traditional tobacco products. Unfortunately, this new form of smoking carries its own risk to pets. Dogs often are drawn to the aromas of the flavored nicotine oil cartridges, and some have been known to chew on the cartridges or even ingest them. This means they’re ingesting the nicotine equivalent to eating a whole cigarette or more—exposing them to the risks of oral and other cancers. 

Cats are vulnerable to another risk from e-cigarettes. One of the main ingredients in the oils used in e-cigarettes is propylene glycol. Exposure to this chemical can lead to a disorder called, “Heinz body anemia,” which reduces the amount of hemoglobin in red blood cells, thus impairing their ability to carry oxygen. Symptoms include discolored skin, fever, loss of appetite, pale lips and gums, and discolored urine.

The best health advice for both you and your pets is—if you don’t smoke, don’t start. And if you do smoke, quit


Cecily Kellogg is a pet lover who definitely has crazy cat lady leanings. Her pets are all shelter rescues, including the dog, who is scared of the cats. She spent eight years working as a Veterinary Technician before becoming a writer. Today she writes all over the web, including here at Figo.

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