Veterinarians are asking pet owners to watch their weed, because more pets are showing up high and sick.

Dr. Billy Griswold, a vet at the Emergency Animal Clinic in Scottsdale, Ariz., told KCTV that he's seen double the number of cases of animals ingesting marijuana over the past few years. KCTV reports that the increase in marijuana treatments "directly coincides" with the opening of medical marijuana dispensaries in the state, starting in December 2012.

The clinic has five facilities that have reported upwards of 24 cases of pets eating weed every month.

Of course, that's just one clinic in one state, but vets in Colorado -- where recreational pot shops opened their doors earlier this year -- are reporting the same problem, according to ABC News.

The natural stuff isn't toxic to animals, but it can give them an upset stomach and other side effects. The real danger is in synthetic marijuana, which can kill pets, Griswold said.

"We have seen a couple fatalities with [synthetic marijuana]," he told KCTV. "There are more serious side effects and longer treatments associated with that."

In fact, some vets condone the use of medical marijuana as a treatment for ailing pets. Laura Bugni-Daniel said her dog is as happy as a (high) clam, despite his sickness and old age, after she started feeding him "magic cheese."

Still, Griswold warns that it's high time you hide your stash.