While many will soon be off to farmer’s markets buying bushels of harvest apples, pumpkins, and corn, others will be rushing to the nearest drug store for over-the-counter allergy medications and boxes of tissues.

Fall can be the worst time of year for people with seasonal allergies. Along with dropping temperatures and changing vegetation, weeds and other plants release pollen into the air and outdoor molds grow under fallen leaves, triggering allergy symptoms for nearly 40 million Americans.