Pollen is very fine plant material whose role is to fertilise female flowers to reproduce. Pollen from trees, shrubs, grasses and weeds can be inhaled, causing hay fever (allergic rhinitis) and asthma symptoms. Pollen may travel long distances, so trees, grasses and weeds in your general area can cause allergy and asthma symptoms.
Follow the links below to find trusted information about the effects of pollen.
Last reviewed: October 2016