ISHEN is the new International Society for Hepatic Encephalopathy and Nitrogen Metabolism. The Society’s origins date back to 1971, when a Working Group led by I. Szám, D. Müting and V. Bräutigam organized an International Symposium on Ammonia Metabolism. Held in Budapest in May 1972, this first symposium featured Sir Hans Adolf  Krebs’ presentation of the newly discovered urea cycle.