Insecticides are the most common cat poisons. All the top 10 cat poisons are household products in one way or another. All these poisonings could be prevented with some diligence and care from the cat owner. Most of these poisons are chemicals made for human use in one way or another. The top two are insecticides designed to kill fleas and other parasites and they are used either carelessly or a product design for a dog is used on a cat. It’s all preventable with education and a bit of care.