The author examined the gut permeability using the test with lactulose, mannitol and D-xylose in patients with coeliac disease. The investigation comprised 30 patients with coeliac disease before they started a gluten- free diet. As control group served 30 patients without organic affliction of the digestive tract. Intestinal permeability is significantly greater when using the indexes lactulose/mannitol and lactulose/D-xylose in patients with untreated coeliac disease. In 23 patients the authors followed-up the value of intestinal permea- bility before the gluten-free diet and 2–6 months after adherence to the diet (checked by reduction or normalization of antibodies against gliadin, and/or endomysin and reticulin). The value of gut permeability assessed by indexes lactulose/mannitol and lactulose/D-xylose declined significantly, however, they did not reach normal values. The test of intestinal permeability is a suitable supplement, a non-nvasive test in the diagnosis of coeliac disease and monitoring of compliance of gluten-free diet.

        Key words: coeliac disease – gluten-free diet – intestinal permeability – lactulose – mannitol – D-xylose