Lactulose is a synthetic sugar used primarily as a laxative to treat constipation. It works by drawing water into the intestines, which softens the stool and promotes bowel movements. It is often prescribed for patients who have difficulty passing stool due to various medical conditions. In addition to its use for constipation, lactulose is also effective in managing hepatic encephalopathy, a condition caused by liver disease. By reducing the absorption of ammonia in the intestines, it helps lower ammonia levels in the blood, improving brain function in affected individuals.