To identify the allergenic components of honey we studied 22 patients with a history of systemic allergic symptoms following honey ingestion. The group of honey-allergic patients was compared with three control groups: 10 subjects sensitized to artemisia, 10 with honey bee venom allergy and 10 without a history of atopy or bee sting reactions. The allergological tests included skin tests and RAST with three different kinds of Swiss honey (dandelion, forest and rape), pollen of compositae species, celery tuber, extract of bee pharyngeal glands, honey bee venom and bee whole body extract. The results show that 3/4 of honey-allergics are sensitive to dandelion honey and 13 of 22 also to compositae pollen. Nine of the honey allergic patients were sensitized to honey bee venom, 3 also to bee pharyngeal glands and to bee whole body extract. Analysis of diagnostic tests and RAST inhibition studies suggest that besides compositae pollen other allergens, most likely of bee origin are important. In honey allergics primary sensitization may be due either to the honey itself, to airborne compositae pollen or even to cross-reacting bee venom components.