Do you ever notice that some cats act really crazy after a sniff of catnip. My older cat, Mollie does. Other cats like my younger cat Millie ignore the herb completely. Roughly 70% of cats respond to cat nip but many react only mildly. Those cats who do like cat nip tend to respond in amusing ways. My cat Mollie jumps and rolls around. Some rub, roll sniff and lick. A cats response to cat nip seems to be genetically predetermined. Male cats are more sensitive to it than females. When cat nip does have an effect, it stimulates the brain much like feline sex hormones do.  Most cats will respond my acting silly then falling asleep. Cat nip has no harmful affects, so it’s OK to give your cat some every now and then. The cat nips affect lasts about an hour. It can come in handy when you want your overweight cat to play a little bit longer. So make sure that your cat has some cat toys containing cat nip, she will like the experience!