There are some pet insurance policies that cover accidents only. What means is that it helps cover vet costs to treat accidental injuries, which usually include broken bones, poisonings and ingesting foreign objects (like tennis balls, a common cause of accidental injury). It does not cover vet costs to treat illnesses. These are usually the least expensive type of insurance plan. Our advice: don't buy one. It's a better use of your money - and you'll be much more satisfied with your plan in the long run - to buy a comprehensive policy that covers accidents and illnesses.