Résumé : It is justified to choose the urea I3C breath test instead of the urea 14C breath test for detection of Helicobacter Pylori gastric infection ? When a choise has to be made between two isotopic methods, the first one needing the use of radioactivity and the second one not, it is reasonable, if accuracy is similar, to prefer the second one. Accuracy, reproductibility andfeasabilityfor the breath test using urea 13C were found to be more favourable.