Aspirin, a mysterious and remarkable pain remedy derived from willow bark, has been shown to help prevent breast cancer, Alzheimer's, heart attacks, and even skin cancer. It can also double, or even quadruple, the risk of ulcers. In fact, as this piece in the New York Times points out, all non-steroidal anti-inflammatory drugs, affectionately called Nsaids, increase the risk of ulcers. The Times reports that risk increases in magnitude as the dose of the aspirin increases, and that some studies have suggested that one-third of aspirin-induced ulcers are
related to over-the-counter aspirin use. The excess ulcer bleeding risk
associated with aspirin use is estimated at 5 extra cases per 1,000
patients per year.
Read more about aspirin and ulcers from the American College of Gastroenterology.