FYI: Can humans get high on catnip?

While cats may feel effects from marijuana—no word on whether Sir Harry Paus actually likes the experience—"kitty pot" does not have a reciprocal effect on humans.

In the late 1960s, some researchers reported catnip gave people a marijuana-like high, but it turned out they had simply mixed up the two plants. As veterinarian Arnold Plotnick of Manhattan Cat Specialists in New York wrote to me in an email, "Think about it… catnip is cheap and legal. If it had a significant effect on people, everyone would be smoking it."

Meanwhile, cats do feel effects from marijuana, but it may be scary for them. "Animals can't understand they're being intoxicated, therefore it can cause considerable anxiety," says Bruce Kornreich, associate director of the Cornell Feline Health Center in upstate New York.

It's not clear why the active chemical in catnip, nepetalactone, doesn't affect humans, Kornreich says. Pot affects cats because like many mammals, including humans and dogs, cats have receptors in their brains for pot's active chemicals, cannabinoids. Cannabinoid receptors make pets susceptible to feeling symptoms when they inhale secondhand smoke or, more commonly, accidentally eat their owners' stashes. (It's actually a bigger problem with dogs, he says, because dogs eat everything.)

Kornreich has seen pets come into veterinary emergency rooms after marijuana exposure. "The pets are presented for anxiety, active heart rate, acting a little unusual," he says. "They may react differently to sound and to being touched" perhaps because, like humans, drugs alter their perception.

Kornreich urges pet owners to take their pets to a vet if this happens, adding that vets are not required by law to report marijuana they run into during their practice. Most veterinarians care more about making pets better, he says. "It's more just focused on the well-being of the patient."