Nine helicobacter-positive pet dogs with upper gastrointestinal signs were studied to evaluate the effect of a triple therapy, normally applied to humans for the eradication of gastric helicobacters, on clinical signs and gastric histology, as well as the recurrence of helicobacters after eradication in an extended follow-up in four dogs. Endoscopy was performed at entry to the study and repeated after eradication therapies and additional treatments. If the triple therapy (amoxycillin, metronidazole and bismuth subcitrate) failed, tetracycline and omeprazole were prescribed. Additional therapies were instituted if clinical signs persisted after eradication therapies. Helicobacter status was verified from gastric biopsy specimens by the urease test and histological examination, and in a few dogs also by brush cytology. Triple therapy eradicated gastric helicobacters in 7/9 dogs; gastric helicobacters were also eradicated in one dog treated with tetracycline and omeprazole. Eradication of helicobacters resulted in significant improvement, but not total resolution, of clinical signs. Subsequent additional therapies resulted in further alleviation of clinical signs. Neither triple therapy nor additional therapies had a significant effect on gastric histological changes. Gastric helicobacters recurred in 4/4 dogs within three years of the eradication treatment. Because canine gastric helicobacters alone were not definitively shown to induce clinical signs, routine eradication therapy seems not to be warranted at present.