The authors examined the intestinal permeability using the lactulose mannitol test in 13 women, mean age 45.7 years with a confirmed food allergy before they were on an elimination diet. The intestinal permeability did not differ significantly in these patients as compared with healthy volunteers. The intestinal permeabiity test with lactulose and mannitol thus cannot be recommended on the basis of these results for the diagnosis of food allergy.