What's the noun for catnep? Here's the word you're looking for.
catnip
Any of the about 250 species of flowering plant of the genus Nepeta, family Lamiaceae, certain of which are said to have medicinal qualities.
Nepeta cataria and Nepeta grandiflora (and perhaps other species), which are well-known for causing an apparently harmless pheromone-based intoxication among certain cats.
(figuratively) Something that causes excitement or interest.