When a cat, dog or other pet is sick, it’s not uncommon for the pet to stop eating and/or drinking. Cats in particular are prone to dehydration when they stop eating, as many cats who eat wet cat food get a good percentage of their fluid from their food. In addition, pets who are vomiting or suffering from diarrhea are even more prone to dehydration, since they have a reduced water intake, in addition to the fact that they’re actively losing fluids.