Taking an aspirin every other day may be a way for adults to avoid developing asthma, researchers suggest.
Aspirin can trigger asthma attacks
A US study of 22,000 people found the painkiller reduced the risk of being diagnosed with asthma by 22%, possibly by acting against inflammation.
Experts said it might shed light on the reasons for adult-onset asthma, but queried how useful it would be to use aspirin as a means of intervention.
Aspirin can trigger asthma attacks among those with the condition.
Although it was not the primary reason for doing the work, the scientists believe their findings have important implications and should be researched further.
The American Journal of Respiratory and Critical Care Medicine study was designed to look at whether aspirin reduced the risk of heart attacks, which it found it did.
In addition to the 44% reduction in heart attacks, those taking a low-dose of aspirin every other day lowered their risk of receiving an asthma diagnosis by 22%.
Lead researcher Dr Tobias Kurth, from Brigham and Women's Hospital in Massachusetts, said: "These results suggest that aspirin may reduce the development of asthma in adults."
The researchers believe it could have something to do with aspirin's action against inflammation.
He cautioned: "They do not imply that aspirin improves symptoms in patients with asthma.
"Indeed, aspirin can cause severe bronchospasm in some patients who have asthma."
Around 10 million people are estimated to have asthma in the UK.
Recent work estimated one in five with asthma are at risk of having a severe reaction to the drug - twice as many as previously estimated.
Professor Ian Hall, from Nottingham University, said it was conceivable that aspirin reduced the risk of late-onset asthma - asthma that develops in adulthood rather than childhood.
"If confirmed by future studies, this would be of scientific interest and might throw light on the mechanisms underlying development of the disease."
But even if this is the case, he questioned how helpful it would be to use aspirin in this way.
"From the study figures, you would have to treat 1,000 people to prevent about three cases.
"Plus aspirin can cause other side effects, including bleeding in the gut," he said.
Professor Martyn Partridge, of the British Thoracic Society and Asthma UK, said: "The relevance of this to the overall 'epidemic' of asthma is limited - most asthma develops in childhood when the use of aspirin should be avoided for other reasons."