The exact cause of ulcers is not known. A relationship between smoking cigarettes and ulcers, especially duodenal ulcers, does exist. The 1989 Surgeon General's report stated that ulcers are more likely to occur, less likely to heal, and more likely to cause death in smokers than in nonsmokers. Doctors are not really sure, but smoking does seem to be one of several factors that work together to promote the formation of ulcers. Most peptic ulcers are caused by this bacterium.
Stomach acid is also important in producing ulcers.
Normally, most of this acid is buffered by the food we eat. Most of the unbuffered acid that enters the duodenum is quickly neutralized by sodium bicarbonate, a naturally occurring alkali produced by the pancreas. Some studies show that smoking reduces the bicarbonate produced by the pancreas, interfering with the neutralization of acid in the duodenum. Other studies suggest that chronic cigarette smoking may increase the amount of acid secreted by the stomach. This research tracing the relationship between smoking and ulcers strongly suggests that a person with an ulcer should stop smoking.