Pollen mixtures used as health food may be a harmful source of allergens.

We describe herein one case of systemic anaphylaxis due to the ingestion of an undefined mixture of pollens, sold as a dietary supplement. The patient, who suffered from rhinoconjunctivitis due to grass pollen (with sensitization to several trees), had a severe episode of anaphylaxis immediately after eating this health food. The episode required emergency care. We attempted to study the pollen mixture responsible, but no pollen granules could be identified. We prepared a solid phase with the pollen mixture, and we observed a RAST positivity with the patient's serum and pools of sera containing specific IgE to trees. Furthermore, a RAST-inhibition assay of the patient's serum showed highly positive results with grasses, birch, alder and Compositae. Therefore, we concluded that the pollen mixture contained determinants capable of cross-reacting with the patient's IgE. This case report is evidence of the possible risks due to the use of undefined herbal products by allergic patients.