Fetor hepaticus or foetor hepaticus (see spelling differences), also known as breath of the dead, is a condition seen in portal hypertension where portosystemic shunting allows mercaptans to pass directly into the lungs. American and British English spelling differences are one aspect of American and British English differences. In Medicine, portal hypertension is Hypertension (high blood pressure in the Portal vein and its branches In Organic chemistry, a thiol is a compound that contains the functional group composed of a Sulfur atom and a Hydrogen atom (-SH lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive It is a late sign in liver failure. Liver failure is the inability of the Liver to perform its normal synthetic and metabolic function as part of normal physiology Other possible causes are the presence of ammonia and ketones in the breath. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor A ketone (pronounced as key tone) is either the Functional group characterized by a Carbonyl group (O=C linked to two other Carbon atoms or The breath has a sweet, faecal smell to it. Breathing takes Oxygen in and Carbon dioxide out of the body Aerobic Organisms require oxygen to create energy via respiration, in Sweet is one of the five Basic tastes and is almost universally regarded as a pleasurable experience Feces, faeces, or fæces (see spelling differences) is a waste product from an animal's digestive tract expelled through the Anus