On the internet, I don’t think you’ll find a clean clear answer to the question, “is it safe for cats to eat catnip?” You will find some answers about the safety of humans consuming catnip. You might know that catnip is used by humans as well. There is catnip tea, for example. It has a calming effect. In fact catnip has been accredited with many health benefits some of which are no doubt exaggerated.
Cats play with catnip toys very vigorously. Sometimes the contents are released and therefore they could be eaten. It is said that cats eat the catnip to promote the release of the chemical in it which provides the reaction that the cat desires.
There is still more to know about exactly what goes on when the chemical in catnip stimulates the cat’s brain. We don’t know all there is to know about how catnip works. This probably explains why we don’t know whether it’s safe for a cat to eat catnip.
Perhaps the answer is this: cats don’t eat catnip and if they do eat it, they only do so in very small amounts which are not harmful. Perhaps we should trust the cat. Cats can be confused about the safety of ingesting manmade products such as antifreeze but catnip is a natural product and animals don’t eat natural things which are harmful to them.
The Humane Society says that when cats eat catnip, which I think is quite rare, incidentally, it has a mellowing effect, which is the opposite of what initially happens when a cat smells catnip. However, after a cat has been excited and stimulated by smelling catnip I think you will find that he will chill out, lying next to the catnip toy for example.
The common sense answer to the question in the title is that it is safe for cats to eat small amounts of catnip but it may well be unsafe for a cat to eat more than small amounts but as this will never happen under normal circumstances, there isn’t a problem.