The advice to take an aspirin a day, which became dogma by the 1990s, was based on flawed science, say researchers from Canada's University of Alberta.
The researchers discovered that 40 percent of Albertans over the age of 50 take aspirin to prevent heart disease, even though they have never suffered from the problem.
In reviewing three major studies, the researchers discovered that aspirin's risk of causing serious stomach bleeding was far greater than its ability to prevent heart disease. In other words, the risks outweighed any benefits.
Although aspirin is known to trigger stomach bleeding, it also causes cancer, and this was the major cause of death in one of the studies the researchers reviewed.
Instead of taking aspirin, people can protect themselves against heart disease more safely by not smoking, eating a Mediterranean diet and exercising, the researchers say.