Lactulose has been used for 40 years in the treatment of constipation [10] and for more than 30 years for encephalopathy.The dosages used in PSE are up to four times higher than those usually applied in constipation. No putative or definite evidence of mutagenic, genotoxic or teratogenic effects of lactulose has been obtained in human use. Animal studies in rats and rabbits also did not reveal any teratogenic or reproduction-toxicologic effects, and even high dosages have had no deleterious effects(6)