Fruit flies do not bite humans but are they still dangerous? You may have seen red marks after killing one, isn't this blood? Find out now!Missing: pies. Serious Fruit Flies Problem? Find out here do fruit flies bites or not?Missing: pies. No, those tiny dots flying erratically in your kitchen are not hallucinations, but rather fruit flies. They don't bite, but they can carry bacteria from one source to.