lactuloseEnglishOxford Dictionary of Englishlactulose /ˈlaktjʊləʊz , ˈlaktʃʊləʊz/ ▸ noun [mass noun] Chemistry a synthetic sugar with laxative properties. It is a disaccharide consisting of glucose and fructose units. – ORIGIN 1930s: from lacto- ‘of milk’, perhaps on the pattern of cellulose.