Lactulose is a synthetic disaccharide

composed of galactose and fructose, that is not absorbed by the human small intestine.

Lactulose reaches the large intestine unchanged, where it is metabolised by the large intestine bacteria and then unfolds its therapeutic effect:

  • Stimulation of the growth of health-promoting bacteria in the gastrointestinal tract.
  • Increases intraluminal gas formation and osmolality, thereby reducing transit time and intraluminal pH, which has a positive effect on constipation.
  • Promotes the increased uptake of ammonia by colonic bacteria. The bacteria utilise the deposited ammonia in the colon as a source of nitrogen for protein synthesis. This reduces the non-ionic diffusion of ammonia from the colon into the portal vein system.

Lactulose Application

Detoxifying Effect 

Hepatic Encephalopathy Treatment 

High Dose

> 90 mL per day (> 60g per day)

Laxative Effect

Constipation Treatment 

Medium Dose

30-60 mL per day (20-40 g per day)

Prebiotic Effect


Low Dose

15 mL per day (10 g per day)

Lactulose is a versatile and safe medication suitable for people of all ages, including those with sensitivities to medication.

It is commonly used as a laxative during pregnancy, for pediatric patients, and in nursing homes. It has been shown to have a beneficial effect on the activation of the natural microbiome.

Its well-known safety profile makes it a suitable option for long-term use and has a low caloric value (0.1-1 kcal/g).