Lactulose is a laxative. It makes the stool softer and easier to pass, by drawing water into the bowel. It is not absorbed into your body. It is used to treat: • constipation (infrequent bowel movements, hard and dry stools) • hepatic encephalopathy (a liver disease causing confusion, tremor, decreased level of consciousness including coma). This is also known as a 'hepatic coma'.