Cats need to be dewormed internally and externally even if they don’t go out. Because cats are meat-eating animals, there are a small amount of parasites in their meat. Cats that eat raw meat need to be dewormed even more. Furthermore, we will be exposed to parasites when we go out. External things, among them, are easy to bring bacteria and parasites home. Hugging a cat will bring parasites into the cat's body, so cats must be dewormed every 3 months.