The Harvard Heart Letter explains that aspirin doesn't have to be in contact with stomach cells to harm them.

Putting an enteric coating on aspirin was an attempt by the pharmaceutical companies to prevent the sometimes adverse effects of aspirin -- ranging from low-grade pain to bleeding -- on the gastrointestinal tract that affects some people but does not seem to affect others.

The idea behind enteric coating is to keep the stomach cells apart from the aspirin for as long as possible.

The special report by the Harvard Health Letter says that even when the pill dissolves in the intestines, the medicine gets into the bloodstream and is carried to all parts of the body -- including the cells lining the stomach. Once there, it blocks the COX-1 enzyme. Stomach cells need COX-1 in order to churn out compounds that protect them from the powerful acids that digest food, the newsletter says.