How much penicillin should you give your cat for an eye infection?

You don't want to give your cat penicillin. If the cat has a puncture wound, it will become or already has become an abscess. That is where the wound does not heal properly from the inside out and closes over with the infection trapped inside. Take your cat into a Veterinarian to have it checked out. Normally they will clean out the abscess and put a penrose drain in it so it can continue to drain out the infection & then heal properly from the inside to the outside. The Vet will also put the cat on antibiotics, the proper ones for that type of infection.