Funny stuff pops up on my news feed, like this one: "Why does your cat love catnip so much?" Apparently it is some sort of aphrodisiac. IHeartCats.com has this answer:
Catnip, scientifically known as Nepeta cataria, belongs to the mint family. (snip) This aromatic herb contains a chemical compound called nepetalactone that triggers intense behavioral responses in many feline species, including domestic cats, tigers, leopards, and lynx.
When cats encounter nepetalactone, the compound reaches their nervous system and activates specific receptors that stimulate the release of sexual pheromones. This neurochemical cascade produces the characteristic euphoric behaviors cat owners frequently observe : rolling, rubbing, stretching, jumping, and sometimes drooling.
Lucky moggies. If there is a human equivalent, other than booze, I bet it's illegal.