Patients entered into study will be randomly assigned to receive either a single, 1 gram oral dose of azithromycin or a single, 1 gram oral dose of ciprofloxacin. Patients entered into study will be assigned a consecutive study number which will have been previously randomly assigned to one of the two treatment regimens, and this randomization will be done using a computer generated random number list with a fixed block length of 4. Study drugs will be administered after completion of the four-hour observation period, and at least 2 hours after the last food intake. The time of administering study drug will be considered as the beginning (the “0” hour) of the study. For patients who vomit within 10 minutes of ingestion of study drug, the dose of the study drug will be repeated. For this purpose, all study drugs will be available in duplicate. Such events will be recorded, and data of these patients will be carefully evaluated. The study drugs will be prepared in identical form to allow for blinding of treatment. Randomization will be done by Pfizer, USA who will also provide coded study drugs.