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Last reviewed on: June 29, 2009
Arrow BulletEnvironmental Allergies

What are common plant allergens?

Ragweed, shown below, is the most common cause of seasonal allergies. It's estimated that 75 per cent of people with hay fever are bothered by ragweed.

A young ragweed plantMale flower with pollen clusters
A young ragweed plant Male flower with pollen clusters

Among North American plants, weeds are the most prolific producers of allergenic pollen. Grasses and trees, too, are important sources of allergenic pollens. You can identify common weeds and grasses found in Ontario by visiting www.ontarioweeds.com.

Dandelions shed airborne pollen but cause limited allergies because the pollen is heavy and tends to fall straight down rarely reaching human noses. The floating fluff is actually the seed, not the pollen, and does not cause allergies.

This web page is for information purposes only.
It is NOT a substitute for professional medical advice.

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