Haemorrhapc Syndrome (HS) or 'Hitra Disease' currently constitutes the most important disease problem in Norwegian salmonid farming. Histopathological and chemical flndings strongly support the hypothesis of HS being a multifactorial disease complex in wh~ch nutritional and/or metabolic disorders are important components. The resemblance to vitamin E/selenium deficiency syndromes in other domesticated animals is discussed.