Catnip is an herb. Some say it is related to mint, oregano or basil. About half of cats are genetically likely to respond to the effect of the active oil in catnip,nepetalactone. It is not certain what part of the brain is stimulated by this ingredient but it is not harmful to the cat and can be used to help increase use of items like scratching posts or facial marking combs. Many treats have this to help stimulate play. —John Ciribassi, DVM, DACVB
The aroma of catnip in cats is thought to be quite pleasurable. It has no other significance and seems to be a genetic accident. It is an autosomal dominant trait, so not all cats are sensitive. —Elizabeth Colleran, DVM, DAVBP (feline practice)
