About this information
This NHS content is written for people in England. Medicine names, availability, prescribing and services may differ in other countries.
Lactulose is a laxative taken to treat constipation (difficulty pooing).
It's also taken to help a condition caused by severe liver disease called hepatic encephalopathy.
Lactulose comes as a sweet syrup that you swallow.
It's available on prescription and to buy from pharmacies.
View the original NHS website page ↗. Refreshed 19 August 2026.
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