Hello, I am sorry to hear about your flu shot reaction. Regarding echinacea, people who have allergies to marigolds, daisies, chrysanthemums, ragweed, and other flowers in that same family can have allergic reactions to echinacea (purple cone flower). Otherwise, it is generally safe. If it is possible, start with only a small amount. If your preparation is in a liquid, it is possible for it to tingle a bit on the tongue - this is not an allergic reaction. There is no known interaction between the asthma medication Ventolin and echinacea. My only concern is that hearing that you take Ventolin indicates to me that you may also have allergies, and my not knowing what you are allergic to, it is hard to say that you are or are not sensitive to plants in the same family as Echinacea. A side note, if you take Echinacea and are sensitive to it, you may not know this while you are on prednisone as the prednisone will blunt your immune reaction. I hope this helps. If you are going to go ahead and try the Echinacea, try only a small amount at first.