Helicobacter pylori (H. pylon) is established as the etiologic agent of chronic active gastritis, peptic ulcer, gastric cancer and mucosa-associated lymphoid tissue lymphoma. The development of a vaccine against H. pylori has become a priority to prevent and cure H. pylon infection. The UreB (urease B) subunit is the most effective and common immunogen of all strains of H. pylori and may stimulate the immunoresponse protecting the human body against the challenge of H. pylori. To date no report has documented an edible carrot vaccine against H. pylori. We transformed the gene of UreB into carrot by Agrobacterium-mediated transformation and the regenerated carrot plants demonstrated that the expressed UreB protein accounted for 25 mu g/g roots and was effective to induce immune response in mice. These results suggest that the UreB transgenic carrot can be potentially used as an edible vaccine for controlling H. pylori. (C) 2009 Elsevier Inc. All rights reserved.