Many greyhounds may miss a meal from time to time, or even a whole day of eating. If you are worried about it, you need to do something about it! We, being human, know that when we miss a meal our stomach begins to growl and our disposition turns on the downside. We know we need to eat something to feel better. When a greyhound has an upset stomach from not eating, it may not instinctually know it needs to eat something to feel better. It's stomach may growl, and it will often go outside and eat grass to pacify the discomfort. As the day wears on, it may or may not have thrown up some bile or stomach acid, and it may eat it's meal. If that doesn't happen and it goes on for another day, it may be something more serious than just an upset stomach. In my own home we use intervention, every day if need be, so that our greyhounds' stomachs are continuously metabolizing food and thereby feeling well. Let's just say that several days have passed and your greyhound still is not eating.