If your cat eats an exceptionally large amount of catnip it may produce a minor tummy upset with some vomiting and diarrhea but this is not common. If a cat consumes too much catnip it may just cause a stomachache. Can too much catnip kill.
Some might eat too much of it and feel sick for a while but theres no evidence of cats suffering long-term damage from ingesting or interacting with too much catnip. But these effects are likely to arise in vomiting and diarrhea. If your cat eats too much catnip symptoms. Cats seem to have a natural shutoff valve for catnip.