We challenged in a double-blind manner 46 pollen-allergic patients with 30 g of honey and another 32 patients with a placebo (30 g of syrup). Minor, mostly subjective, symptoms were seen in or reported by 26% of those challenged with honey and 41% of those challenged with placebo. In no case could the symptoms with certainty be related to the challenge. Eight commercially available honeys were examined for allergen activity by RAST inhibition and immunospot methods. Both pollen and insect allergen activity was found in all honeys, and they could cause allergic reactions. However, no serious or even obvious reaction occurred in pollen-allergic patients challenged with honey.