Azithromycin is a member of a new class of macrolides called azalydes. Although azithromycin resembles erythromycine there are significant differences in antibacterial activity and pharmacokinetic profile. Azithromycin is taken up by cells and the intracellular concentrations are significantly higher than serum concentrations. After a single oral dose of Ig, azithromycin has a long lasting effect--the tissue concentrations in the uterine and cervical tissues are kept above the minimal inhibitory concentration for Chlamydia trachomatis for more than 10 days. In order to achieve the maximal bioavailability and avoid side effects (gastrointestinal discomfort), azithromycin should be taken apart from meals (one hour before or two hours after meals). Azithromycin has no hepatotoxic potential and the possibility for drug interactions is not apparent. It is also recommended for use in pregnant women--FDA category B. A single oral dose of Ig azithromycin is the reasonable choice for the treatment of uncomplicated genital chlamydial infection.