What is lactulose, and why is it given to liver patients?

Non-digestible sugar. Lactulose is a non-digestible sugar. When ingested, it is metabolized by normal colon bacteria into small fatty acids, acetic acid, & lactic acid. The extra h+ attracts & binds ammonia (nh3) from the blood creating ammonium (nh4+). This is trapped in the colon & defecated out. This reduces the overall blood ammonia concentration which worsens hepatic encephalopathy. But it also causes diarrhea.
Lactulose. Lactulose is used to remove ammonia from the blood of patients with advanced liver failure in an effort to prevent liver coma. It removes ammonia from the blood and into the colon so it can be removed from the body.