Ammonia

A colourless, pungent gas that dissolves in water to form ammonium hydroxide, an alkaline solution (see alkali). Ammonia is produced in the body and helps to maintain the acid–base balance. In severe liver damage, the ability of the liver to convert ammonia to urea is reduced. This leads to a high level of ammonia in the blood, which is thought to be a cause of the impaired consciousness that occurs in liver failure.