- Background: The aim of the study was to examine effects of Helicobacter pylori eradication on chronic idiopathic urticaria (CU) with and without positive aulogous serum skin test (ASST). Methods: Seventy-eight patients with CU were checked for the positivity ASST and H. pylori urea 13C-urea breath test (13C-UBT). Twenty-one patients were with both positive ASST and positive 13C-UBT (group A), and 24 patients were with negative ASST and positive 13C-UBT (group B). All patients with positive 13C-UBT received a 14-day, open treatment with amoxicillin 1 g b.i.d., clarithromycin 500 mg b.i.d., and omeprazole 20 mg b.i.d. H. pylori eradication was assessed by a second 13C-UBT after 8 weeks. In control group, 33 patients with CU were included. The effect of H. pylori eradication on CU was evaluated by urticaria activity score (UAS), measured at study entry and at 8 and 16 weeks. Results: At week 8, baseline UAS reduced from 4.7 ± 1.1 to 2.4 ± 1.4 (p = .027) in group A and from 4.3 ± 1.5 to 2.3 ± 1.2 (p = .008) in group B, without statistically significant difference between the two groups. In control group and in six patients with H. pylori eradication failure, no changes of UAS were noted. Conclusion: Eradication of H. pylori infection by triple therapy significantly and equally reduces UAS in CU patients with positive and negative ASST.