Colonization of the ferret stomach by Helicobacter mustelae has been suggested as a possible animal model for Helicobacter pylori-associated gastroduodenal disease of humans. Our study was designed to determine whether antimicrobial chemotherapy could eradicate H. mustelae from ferrets. Triple antimicrobial therapy combining amoxicillin, metronidazole, and bismuth subsalicylate was successful in eradicating the organism from 5 of 7 (71%) adult ferrets. Despite apparent in vitro susceptibility, neither chloramphenicol monotherapy nor a polytherapeutic regimen combining tetracycline, metronidazole, and bismuth subsalicylate proved effective in the eradication of H. mustelae. Several strains isolated after unsuccessful polytherapy showed markedly increased resistance to metronidazole. These preliminary findings are similar to results of H. pylori treatment trials with humans and suggest that the ferret may be a useful model for evaluating and comparing potential antimicrobial modalities for the eradication of H. pylori.