Catnip is not bad for cats. It is not toxic, not addictive, and not a drug in any sense that should worry you. The reaction looks dramatic, which is why the question comes up, but the plant is a mint, and the worst it usually does is an upset stomach from eating too much of it.
What follows is the practical version: how it works, what "too much" looks like, the rare cat that gets cranky, and when to stop offering it.
What the reaction actually is
Nepetalactone, the oil in Nepeta cataria, binds to receptors in the nose and sends a signal to the parts of the brain that handle emotion and behaviour. For about two in three cats that produces 10 to 15 minutes of rubbing, rolling, and play, then a stretch of calm. After that the receptors ignore the scent for 30 minutes to two hours.
The remaining third never respond. That is inherited, not a sign of a healthier or more serious cat.
Kittens usually do not react until they are three to six months old. Offering it earlier is harmless and also pointless.
It is not a drug, and they do not get hooked
Cats do not develop a physical dependence on catnip. They do not need more of it over time to get the same reaction. They do not go looking for it the way an addicted animal goes looking for a substance.
What they can do is habituate. A toy left out all week stops registering, both because the oils evaporate and because a constant smell stops carrying information. That looks like "it stopped working." Put the toy away between sessions and the same cat will respond again.
The plant does not damage the liver, kidneys, or nervous system. There is no fatal dose in any realistic household quantity.
Can they eat it?
Yes. Eating a little often makes them sleepy rather than hyper, which is the opposite of sniffing it.
A small pinch of dried leaf is plenty. Fresh is stronger than dried. They do not need it as food; they eat it because they want to.
The problem is volume, not the plant itself. A cat that empties a bowl of loose herb may vomit or have diarrhoea. That is fibre irritating the gut, and it resolves once the plant has passed. Take the rest away, offer water, and leave it. If vomiting continues or the cat is lethargic well after, call the vet, as you would with any other dietary upset.
A tablespoon of dried catnip is a sensible ceiling for a session. More than that is not more effective. It is only more likely to come back up.
Cats that inhale the stuff and then try to eat the bag are better off with a stuffed toy they cannot empty.
The cranky minority
Most cats get playful or sleepy. A few get irritable: swatting, overstimulated, not wanting to be touched. That is not aggression in the territorial sense. It is a cat whose sensory system is busy and who wants space.
If yours is in that group, stop offering catnip. There is no benefit in pushing through it. Silver Vine is worth a separate, careful try, because it uses different compounds and does not always produce the same mood. If that goes the same way, skip both herbs and use movement and texture instead.
Do not punish the reaction. End the session, put the toy away, and give them a room.
How often, and what quality
A few times a week is enough. Daily use is not dangerous; it is how you teach a cat to ignore the smell.
Buy organic if you can. Catnip is a crop, and conventional herb can carry pesticide residue. That matters more than it does for a plant you only look at, because cats lick and chew it.
The toy around the herb matters too. Thin polyester with glued-on eyes is a swallowing hazard once the seam goes. The plant can be perfectly safe inside a badly made object.
A short list of actual rules
- Offer it a few times a week, then put it away
- A pinch or a well-filled toy, not a pile on the carpet
- Watch the first few sessions if you have not used it before
- Stop if the cat gets snappy rather than playful
- Green, sharp-smelling herb. Brown hay-smelling herb is spent
- Kittens under three months will usually ignore it, which is fine
We fill Le Croissant with organic catnip buds and Silver Vine fruit, at least 30g of it, inside reinforced OEKO-TEX cotton, partly so the cat can have the reaction without emptying a bag of loose leaf onto the floor. No plastic parts, no dyes, nothing small enough to come off. The second herb is there for the third of cats that catnip cannot reach.