The epidemiologic study by Peleg et al 1 supports the growing evidence that regular aspirin use reduces the risk of colorectal cancer. In their editorial, however, Waterhouse and Brenner 2 discuss some of the problems and contradictory data associated with aspirin cancer chemoprevention. They state that chemoprevention is aimed at a healthy population and, therefore, untoward side effects of aspirin are intolerable. In practice, however, patients who may benefit from aspirin chemoprevention are likely to be at an increased risk of colorectal cancer. Thus, while these patients may not present with clinically advanced disease, they can hardly be described as healthy either. In such at-risk patients, aspirin may have potential, since the incidence of side effects would be justified. 3 Another issue they raise is the contradictory data of Gann et al. 4 This study found that aspirin in doses sufficient to prevent myocardial infarction did not confer protection against