CHESAPEAKE, Va. — If you’re a pet owner, you probably buy plenty of toys and products for your dogs or cats.

“Counterfeiting is big business ... you are running the risk that that is not a product you want,” veterinarian Dr. Denette Cooke warned.

Believe it or not, big business cashes in on pet products and medications and if you’re not careful, you can be putting yourself and your pet at risk.

“If it is not a veterinary distributor, you run the risk of getting what we call 'gray market products,'” said Dr. Cooke.

RELATED: BENTLEY'S CORNER: Tips for the dog days of summer

“Flea and tick products, in particular, are very common. We’ve seen counterfeit collars, counterfeit topicals that have no medicine in them or they don’t work. We’ve had quite a few people say they bought it online and it's not working,” Dr. Cooke said.

We buy most everything online these days, so how do we know what we are buying for our pets is actually legit? Is there a way to tell?

Look at the packaging, look for any tampering, stickers covering up any directions for use. Also, the pill inside might not match the picture on the front of the box or the dosage might not be accurate.

The EPA has a website and I am sure if you look in the FDA, you’ll find that site too. You’re looking for credible veterinary pharmacies,” said Dr. Cooke.

She added, “We have found heartworm positive cases where people are buying products online and they are coming up heartworm positive and they have not missed any heartworm preventative. That’s because they are getting very expensive heartworm pills with no medicine in it. It's basically a glorified chew.”

RELATED: Bentley's Corner: Protecting against heartworms

There are also counterfeit toys and other pet products that Dr. Cooke says to watch out for. If something seems too cheap, then it is likely a counterfeit product.

Especially with medicines, this is worrisome.

“It’s not coming from a veterinary source, it may be tampered with, it may be the wrong dosing, it could be a glorified pill,” said Dr. Cooke.