All ulcers are not the same.

With the discovery of Heliobacter pylori as a leading cause of ulcers has come the misconception that this bacteria is to blame for all ulcer problems. However, it accounts for just one piece of the puzzle, responsible primarily for those ulcers that previously were attributed to too much acid production or too much stress. There still are people who get ulcers and damage to their stomach from factors totally unrelated to Heliobacter pylori, such as anti-inflammatory drugs, alcohol, severe closed-head injuries, or burns.

Since aspirin (along with nonsteroidal anti-inflammatory drugs such as Advil and Motrin) is the number-one drug taken by Americans, this prospect concerns a large segment of the population. "All of these drugs that people take for aches, pains, and arthritis can cause ulcers and significant damage to the stomach," cautions Thomas A. Miller, chairman of surgery, Saint Louis (Mo.) University School of Medicine. "Of 100 people with ulcer problems, about 60-70% of them have ulcers caused by Heliobacter pylori. The fascinating thing is that the other 30-40% have ulcers for another reason."

Since the late 1970s, Miller and Gregory Smith, director of the university's Surgical Research Institute, have seen various mechanisms evaluated, including acid, bicarbonate secretion, mucous production, and blood flow. All were...