BACKGROUND Helicobacter pylori (HP) have recently emerged as a novel eliciting factor for chronic urticaria (CU). The possible association between HP and CU has enormous potential, as eradicating HP could cure CU. OBJECTIVE We conducted a study to assess the prevalence of HP infection and effect of bacterium eradication on skin lesions in patients of chronic idiopathic urticaria (CIU). METHODS Four hundred sixty patients of CU attending the allergy clinic, SMS hospital, Jaipur during the period February 6, 2004, to February 6, 2006, were screened for possible eliciting factors. Patients with CIU were enrolled and others were excluded. METHODS Sixty-eight patients of CIU and similar number of age and sex matched controls, attending the allergy clinic, SMS Hospital, Jaipur were enrolled in the study. All patients underwent endoscopy with antral biopsy for urease and histopathology to identify HP-associated gastritis. Infected patients were given HP eradication therapy. Eradication of bacterium was confirmed by fecal antigen assay. Subjective response to treatment was judged using chronic urticaria quality-of-life questionnaire (CU-Q 2 oL) while objective response to treatment was judged by need for 'rescue medication' (antihistaminics). METHODS Data were analyzed using Chi square and paired 't' test for their level of significance. RESULTS HP associated gastritis was present in 48 (70.58%) patients, out of which 39 (81.25%) patients responded to eradication therapy. Ten (50.00%) patients without HP associated gastritis showed response to symptomatic therapy. Overall 49 (72.05%) patients responded and 19 (27.94%) showed no response. The value of chi2 was 28.571 (P = 0.003), which showed significant association between presence of HP and response to eradication regimen. CONCLUSIONS The response of HP eradication therapy in infected patients of CIU is significant. HP should be included in diagnostic workup of patients with CIU.