Aspirin is just full of surprises. We’ve known for decades that it treats headaches. More recently, it’s become a safeguard against heart attacks.

Now it seems this humble medicine may help prevent adult-onset asthma. That’s asthma first diagnosed when a person is older than twenty. It may be related to allergies or irritants.

In recent years, scientists have noted that some adults who frequently use aspirin seem to have a reduced risk for the disease. Now, a study reported in the journal Thorax explores that possible link.

The study involved about thirty-seven-thousand healthy women at least forty-five years old. They were divided into two groups roughly the same size. One group took one-hundred milligrams of aspirin every other day. The other group took a placebo.

The women were followed an average of almost ten years. Overall, about eighteen-hundred of the participants were diagnosed with adult-onset asthma during follow-up. But women in the aspirin group were ten percent less likely to develop the disease, compared with those on the placebo.

The researchers weren’t sure why aspirin might discourage asthma. They speculated that the drug inhibits certain immune responses.

They also cautioned that more research is needed before anyone can recommend aspirin to prevent adult-onset asthma. So if you’re worried about this disease, don’t visit the drugstore, visit your doctor.

If you start a new health regimen without medical advice, you may be in for a few surprises… and they might not be pleasant.