Ketones are byproducts that arise in the body during fat digestion. Specifically, ketones are produced when the body uses fats instead of carbohydrates for obtaining energy. Though ketones are not harmful in small rates in the body, abnormally high rates can pose serious threats. When ketones accumulate far over their permissible limit, they cause a condition known as Ketosis. The most Commons ketone in the blood stream is Acetone. Ketosis can lead to ketoacidosis, which is known to cause comas and is mostly fatal. Ketosis is common in diabetic patients. Common symptoms are abdominal pain, nausea, flu symptoms, excessive thirst and breathing difficulty.