You come home to find your cat rolling around on the floor, rubbing his face on a favorite toy and perhaps even drooling a bit, and you know what happened — he got into the catnip again.

But what is it about catnip that makes your cat react this way?

Catnip is a plant in the mint family that produces a chemical called nepetalactone. When a feline inhales nepetalactone, the chemical binds to receptors in the cat’s nasal tissues, which activates sensory neurons in the brain.

This stimulates activity in the olfactory bulb of the brain, as well as the amygdala — the part of the brain that controls emotional responses — and the hypothalamus, which regulates hormones.

Nepetalactone is thought to mimic a pheromone, and it's not the only plant chemical that triggers a response from cats.

Valerian is a flowering plant that contains actinidine, which is a stimulant for cats. Some veterinarians recommend exposing overweight cats to the plant to encourage physical activity.

When cats respond to catnip, they typically roll, drool and chase imaginary critters, but only for about 10 minutes.

Although the animal may continue to chew or rub on the catnip, cats actually become temporarily immune to the effects of catnip. This refractory period typically lasts about 30 minutes, after which they become susceptible to catnip’s effects again.

But not every cat will react the same way to catnip — and some won't react at all.

Response to catnip is hereditary, and it's estimated that 70 percent to 80 percent of felines react to the plant.

Although it's been suggested that catnip can be used as a substitute for marijuana, there's no scientific evidence to back up that premise.

Catnip doesn't have the same effect on humans because our olfactory systems and brains are structurally different.

However, as the video below illustrates, the size of a cat plays no role in whether a feline reacts to catnip. Tigers can appreciate the plant just as much as your tabby cat.

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