An aspirin a day may be good for you--or maybe not.

That's the advertising message Bayer Corp. has agreed to put out to settle Federal Trade Commission charges that it made unsubstantiated claims in a series of aspirin ads that ran from 1995 to 1998. The ads, which featured a loud, pounding heartbeat, claimed that a regular dose of aspirin can reduce the risk of heart attacks and strokes.

The FTC said not all adults are likely to benefit from an aspirin-a-day regime and some may even suffer adverse health effects, such as gastrointestinal bleeding.

To address the FTC's concerns, Bayer will run a $1 million education campaign that will feature a free brochure: "Aspirin Regimen Therapy--Is It Right for You?" And in any future advertising that makes claims about aspirin's role in helping to prevent heart attacks and strokes, Bayer must state: "Aspirin is not appropriate for everyone, so be sure to talk to your doctor before you begin an aspirin regime."

Bayer spokeswoman Anne Coiley said the Bayer ads always advised consumers to "just ask your doctor" before starting an aspirin-a-day diet. "This was a dispute in how effective we were in doing that," she said. "We think what they have asked us to do is legitimate and reasonable."

In related cases, Bayer has reached settlements with the attorneys general of New York and Connecticut, agreeing to pay each state $30,000.

The Food and Drug Administration has recognized that a daily dose of aspirin is effective in reducing the risk of stroke or heart attack in certain groups of people--such as those who've had a stroke caused by a blood clot or suffered a previous heart attack or have angina.

But the FTC said there are no data to prove that aspirin is appropriate to prevent strokes or heart attacks in the general population. For example, pre-menopausal women have a relatively low risk of heart attack. But such women are prominently featured in the company's ads.

The ad's statement, "just ask your doctor," was "inadequate to alert consumers that a medical professional should be consulted," the FTC said.