Ammonia is a nitrogenous molecule which is primarily generated in the gastrointestinal tract. The neurotoxicity of ammonia plays a critical role in the liver's regulation of circulating ammonia levels. In liver disease, an increase in blood ammonia has been long implicated in the pathogenesis of hepatic encephalopathy (HE), a neurological complication of liver disease. However, the clinical value of measuring plasma ammonia in patients with cirrhosis remains controversial. This dilemma was the subject of a debate held at the International Society of Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) meeting in St-Paulin, Québec, Canada in October 2025. This review illustrates the pros & cons of measuring plasma ammonia in the management of patients with cirrhosis.
