San Francisco, California. Many studies have shown that nearly all peptic ulcers (duodenal and gastric) are caused by an infection with the Helicobacter pylori (H. pylori) bacteria unless they are due to the over use of aspirin, or other nonsteroidal anti-inflammatory drugs (NSAIDs). Extensive research made public over ten years ago has also shown that an H. Pylori infection can be completely eradicated with a short medical treatment using metronidazole, bismuth and tetracycline or amoxicillin. One off, complete eradication of the infection spares patient’s considerable pain, but is costly.