Could catnip be causing my cat's drooling, vomiting, and seizures?

Hello, thank you for using Petco Pet Education Center, formerly Petcoach.

It is possible that he has seizures that are unrelated to the catnip. However, it is also possible that catnip could have an effect on a cat who is already prone to seizures (as an epileptic or has some time of congenital brain defect or injury).

While we do not fully understand the effects that catnip has on cats, there has been some recent research that has pinpointed a compound present in catnip called nepetalactone. This component is similar to the opioid molecule (a drug class that includes morphine) and is thought to have a similar effect to that drug group. When a cat ingests this agent, we do see an alternation in behavior and mental status. For most cats this is mild, but in some we do see it progress to stereotypic, repetitive, and abnormal behaviors. Therefore, it is not a big stretch to suspect that this compound's contact with an epileptic brain could lead to the induction of seizures.

So, while I don't think catnip would cause seizures on its own in the normal cat, if your cat is an epileptic (undiagnosed) or has suffered a brain injury then it is possible that catnip could cause him to have further seizures.

I suggest you stop using catnip in all forms (don't even have it in the house) and then start keeping a written log AND videos of his behavior. If this is happening more than once every week or two he needs to go back to the vet so you can talk about other diagnostic testing or to start him on anti seizure medication.

Hope this helps. Best wishes.