Background Upper gastrointestinal bleeding is one of the most frequent causes of morbidity and mortality in the course of liver cirrhosis. Several treatments are used for upper gastrointestinal bleeding in patients with liver diseases. However, supplementary interventions are often used as well. One of them is vitamin K administration, but it is unknown whether it benefits or harms patients with liver disease and upper gastrointestinal bleeding. Objectives To assess the beneficial and harmful effects of vitamin K for patients with liver disease and upper gastrointestinal bleeding. Search strategy We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (February 2004), which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings, The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 1, 2004), MEDLINE (1966 to March 2004), EMBASE (1988 to March 2004), and LILACS (1982 to March 2004). Additional randomised trials were sought from the reference lists of the trials found and reviews identified by the electronic searches. Selection criteria We intended to include randomised clinical trials. Data collection and analysis We intended to summarise data by standard Cochrane Collaboration methodologies. Main results We could not find any randomised trials on vitamin K for upper gastrointestinal bleeding in patients with liver diseases. Authors' conclusions We were unable to identify randomised trials on the safety and efficacy of vitamin K for upper gastrointestinal bleeding in patients with liver diseases. The effects of vitamin K need to be tested in randomised clinical trials. -------------------------------------------------------------------------------- Plain language summary Evidence to establish the beneficial and harmful effects of vitamin K for upper gastrointestinal bleeding in patients with liver diseases is lacking Randomised trials with vitamin K for upper gastrointestinal bleeding in patients with liver diseases could not be found. Valid evidence for or against the use of vitamin K for patients with liver diseases is lacking.