I've taken Quercetin from various brands for about two years. My problem was occasional outbreaks of hives, rather than seasonal allergies, but I do think it has helped. I've noticed that mosquito bites now disappear in the same night or next morning, rather than lasting two or three days. Anyway, I thought others might want to know the nutritional info on the bottle.
In my 200 Tablet bottle, 1 serving is 1 gram Quercetin per 3 tablets, so 333 mg per 1 tablet.
3 tablets also contain:
vitamin C 646 mg
magnesium 50 mg
bromelain 300 mg
quercetin 1 gram
Some other reviews have indicated that you can't take too much of this supplement. However, I've read about side effects and drug interactions with bromelain, so it's a good idea to read up on those before taking bromelain.