Helicobacter pylori is a gram-negative, microaerophilic, spiral bacillus. Infection by this organism is currently believed to be the major cause of type B gastritis. Inflammation and infection may persist for years in the absence of therapeutic intervention. There is currently no approved antimicrobial therapy for gastritis. Clinical investigations have shown that combination regimens including bismuth salts and antimicrobial drugs result in the relief of symptoms, the resolution of histologic evidence of gastritis, the eradication of H. pylori, high rates of ulcer healing, and lower rates of ulcer relapse than have been found with other therapies (antacids and H2 antagonists). A randomized, double-blind, placebo-controlled study design is recommended for evaluation of new therapies. Study participants should have their progress monitored by endoscopy performed at enrollment, at completion of therapy, and 3 months thereafter. Assessment of microbiological outcome is paramount for final evaluation of the patient.