Pets living in households where the owners smoke may be more likely to need pet medication, as they are at a higher risk of developing certain diseases.
Professor Clare Knottenbelt, from the University of Glasgow's Small Animal Hospital, has said cats from homes where occupants smoke are more likely to get lymphoma and oral cancer, while dogs are more at risk of lung, nasal and sinus cancers, reports the BBC.
She told the news provider: "While veterinary medicine is advancing all the time and we have the ability to treat some cancers in pets, it is expensive and provides no guarantees of long-term survival.
"The best way of avoiding damage to your pet's health is to not smoke around them - or better still, to give up."
Professor Knottenbelt added that she is writing a paper that indicates pets are exposed to the same levels of nicotine as children living in a smoking household.
According to the NHS, secondhand smoke contains 4,000 toxic chemicals and puts those who breath it at risk of the same diseases as smokers.