Most Quercetin supplements are sourced from parsley and red onions but there are lots of foods that have it in them - red apples, elderberries, blue berries, kale. You would have to consume a lot of those to get to the dosage required though..LOTS.

Most Quercetin supplements are sourced from parsley and red onions but there are lots of foods that have it in them - red apples, elderberries, blue berryies, kale. You would have to consume a lot of those to get to the dosage required though..LOTS.