Six captive cheetahs (Acinonyx jubatus) with severe gastritis diagnosed by gastric endoscopy and mucosal histopathology were treated with omeprazole, metronidazole, and amoxicillin for 3 wk. Endoscopic biopsies were performed before therapy, immediately after treatment, and 3, 7, and 19 mo after treatment. Macroscopic appearance of the stomach, histologic scoring of gastric inflammation, and the presence or absence of spiral bacteria were recorded. Spiral bacteria were absent histologically immediately after treatment but reappeared in endoscopic biopsies by 3 mo after treatment. Gastritis scores fluctuated widely during the trial but improved in five of six cheetahs by 3 mo after treatment. By 19 mo after treatment, scores were close to the pretreatment scores. Therapy with omeprazole, amoxicillin, and metronidazole was associated with temporary improvement in the degree and distribution of gastritis in some cheetahs with gastritis, suggesting that treatment may be warranted once severe gastric inflammation has been diagnosed.