I routinely take one baby aspirin a day on the recommendation of my doctor. Aspirin is a well-known blood thinner and many others my age are on a similar regimen to help prevent strokes and heart attacks.
Now, as reported by the BBC, aspirin may also help brain function. In a recent study of 500 women (not many) ages 70 to 92, those on aspirin therapy were found to retain much more mental ability over five years, although the aspirin did nothing to forestall the onset of dementia.
The report was skimpy on details and did not say how much aspirin they took, but the results sound reasonable just by increasing the blood flow to the brain. Dementia is a separate problem.