National Geographic
Diphenhydramine is the active ingredient in countless over-the-counter medications. But experts say there are serious risks to taking too much of the drug—or taking it too long.
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The over-the-counter medicine scientists say may raise your dementia risk
Daryl Austin
09:20
Diphenhydramine is the active ingredient in countless over-the-counter medications. But experts say there are serious risks to taking too much of the drug—or taking it too long.
