Watermelon is non-toxic to cats and can be given as a treat from time to time, according to Purina. If you give your cat watermelon, it should be seedless. Watermelon seeds contain trace amounts ...

There are not many health benefits when cats do eat watermelon. They may get some hydration, potassium or vitamin C from the fruit, but "the benefit is likely to be minimal," according to PetMD.