Darlene, there are at least three possibilities. (1) Dandelion pollen
got into the wine and she had a reaction to it. I have never, ever
heard of an allergy to dandelions or their pollen, but admit it is
possible. (2) She had a reaction to something else in the environment
and the dandelion took the rap. (3) She knew it was dandelion wine
and had a hypochondrical reaction. One of my sister-in-laws had a
similar reaction to a crabapple wine after my brother told her it was
white clover wine. He was trying to prove to her that many of her
so-called "allergy attacks" were self-induced. He proved his point,
but she is unforgiving to a fault and he has been living in the dog
house ever since. Moral of this story: do not make a fool of your
spouse if you do not want to live with a fool.

I honestly have difficulty believing your friend's reaction had
anything to do with the dandelions, but I have been wrong before.

How does she react to mead? There is potentially far more pollen in
mead than dandelion wine, but there should be none in either if the
wine was racked a few times and brilliantly clear when bottled.

Jack Keller, The Winemaking Home Page
http://winemaking.jackkeller.net/