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.