A randomized, double-blind, placebo-controlled clinical trial of azithromycin in Campylobacter concisus culture positive patients with diarrhea. The clinical characteristics of emerging Campylobacter concisus in adults is vomiting and persistent diarrhea. Whether patients may benefit from antibiotic treatment is unknown. The purpose of this trial is to investigate whether antibiotic treatment with azithromycin of Campylobacter concisus induced diarrhea can better the symptoms and shorten the duration of illness.