Herb known for its effect on feline behaviour (6)

I believe the answer is:

catnip

(Other definitions for catnip that I've seen before include "treat for moggie" , "Herb of the mint family, attractive to some pets" , "Feline attractor (I, not E)" , "flower" , "Strong-smelling herb" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.