Letting your indoor cat Outdoors can exposed them to contracting infectious diseases especially through fighting with other cats that live in the neighbourhood. The Common serious diseases which are Feline Leukemia, Feline AIDS, abscesses, and upper respiratory infections, among others. Some toxic substances which we use outside to get rid of pest in our garden, plus some outdoor plants which are very toxic to cats and that includes slug pellets and rat poison which are also very dangerous to kittens and cats if it enter their digestive system.