The only way to treat people suffering from celiac disease is to eliminate products containing gluten proteins from the diet. Researches have been carried out to find new sources of gluten-free food; among them, the cattail (Typha spp) can be counted. It is possible to grind its rhizomes and to get a baking flour to make cakes, bread, and biscuits. The objective of the study was to determine the content of gluten fraction in the flour produced from rhizomes of the narrow-leaved cattail that caused a disease response in persons with the celiac disease. The experimental material comprised rhizomes of the narrow-leaved cattail (Typha angustifolia), harvested in three water reservoirs during the winter period (January 2009), i.e. in a pond in the Zielonka Forest (the Province of Wielkopolska), in a lake and a fish breeding pond in Osieczna (near Leszno). The test for gluten was conducted by means of immunoassay methods using the products from an R-Biopharm Company: Cocktail Solution ® and Ridascreen gliadin kit ® Gliadin R7001 (AOAC 120601). The content of total protein was determined by a Kjeldahl method using a Foss Tecator apparatus. The content of Gliadin protein in the extracts was determined photometrically using a Bradford reagent. Based on the results obtained, it was found that the flour from rhizomes of the narrow-leaved cattail did not contain any peptides that caused celiac disease. Thus, this flour can be used in the products for people suffering from this disease. The content of total protein in the flour varied depending on the place where the plants were harvested. The content of the protein fraction in the flour extracts produced from rhizomes of the narrow-leaved cattail was not correlated with the content of total protein in the flour alone.