Catnip effects are usually purring, jumping and running around, and some cats will even rub their faces in it. After all of this activity most cats will calm down and nap for some time. The potency of the catnip will determine how your cat responds to it.
If your feline friend is not enjoying their catnip toy as much it could be because the leaves have gotten old and lost most of their potency. You can put catnip leaves in your cats food or give them a toy that has catnip in it. The effects are the same.
Some cats prefer to eat the leaves but be careful if your kitty has a sensitive stomach. This can cause vomiting or diarrhea in cats with a sensitive stomach or digestive problems. If this happens then you can simply buy your kitty a catnip toy instead.
A catnip toy is a great way for your cat or kitten to enjoy catnip without having any of the stomach problems that can comes with eating the leaves. The cats enjoy the smell of the catnip. When the leaves start to grow old and lose potency you can either refill the toy with more leaves or roll the toy in crushed catnip leaves. Some pet stores even sell catnip sprays. This refreshes the old toy with the catnip scent so that your cat will enjoy it again.
You may find that some cats can get aggressive when they have catnip. If you have never given your cat catnip before it is probably best to test their reaction to it when they are alone. Most of the time when you have two cats they will play together and enjoy the catnip but if one of them reacts badly to the catnip they could fight.
Try putting the cats in rooms by themselves to test their reaction. Make sure that you keep them away from each other until all of the effects are completely worn off. Keep your children away from this experiment too. When you have a naturally aggressive cat it is best to test them this way first.
Usually cats will experience a kind of euphoric feeling when they are in contact with catnip. Not all cats will be affected this way. Not all cats are affected by catnip though. You could have one cat that loves catnip and another that is not affected by it in any way.