vitamin K



  • noun a vitamin found in green vegetables such as spinach and cabbage, which helps the clotting of blood and is needed to activate prothrombin


  • This vitamin relates to a group of chemical quinones, some fat-soluble and others water-soluble, which are synthesized by human gut microorganisms and are found in abundance in brassicas and spinach and in moderate concentration in tomatoes and pig’s liver. Lack of the vitamin causes haemorrhages especially in new born infants. It is usually only administered under medical supervision.