Although the sunflower belongs to the Compositeae family, allergy to sunflower pollen is not common. The occurrence of occupational allergy to this pollen species made it possible to characterize cross-reactive patterns of Compositeae pollens in a human experimental model. A 24-yr-old man developed rhinitis and conjunctivitis over 5 yr of exposure to sunflower pollens, and asthma developed during the fifth year. All respiratory and occular symptoms disappeared after he was removed from exposure, but he had a food allergic reaction while he was eating honey containing 30% sunflower pollens. The diagnosis of occupational allergy was based on history, skin prick tests and RAST to the pollen. Bronchial provocation tests performed after removal from exposure confirmed the sensitivity to sunflower pollens but there was no nonspecific hyperreactivity. It was found by RAST inhibition that sunflower pollen does not cross-react with other Compositeae pollens tested or with sunflower seed. The honey that elicited food intolerance was demonstrated to inhibit significantly sunflower pollen RAST.