We relate our experiences about the number of exacerbations that certain food preservatives such as sorbic acid, benzoic acid, sodium benzoate, metabisulfite and sodium nitrate can provoke in 62 patients affected with ASA-triad in steroid dependent intrinsic asthma with nasal polyps and acute bronchospasm caused by aspirin ingestion, and in 80 patients with chronic urticaria (C.U.) as well as the first assays of the possible usefulness of the HRT (Histamine release test automatized using whole blood) for the etiologic diagnosis process. In the cases of ASA-triad, and after the ingestion of aspirin (alternating with lactose in identical capsule), we consider the result as positive when the reduction of FEV1 is superior to 20% from its baseline value. Regarding the cases of C.U., the symptoms always exacerbate twice as much with the same substance within 24 hours of its administration. We have performed the HRT on 59 patients (14 with ASA-triad, 11 with steroid dependent intrinsic asthma; 20 with C.U. were negative to oral intake of analgesics/additives and 14 with C.U. showed positive results). Successive dilutions were incubated for 30 minutes using: pyrazolones, acetylsalicylate of lysine, sodium salicylate, sodium benzoate and 4-hydroxybenzoic acid which did not produce liberation of histamine in 100 controlled individuals. All the determinations were done in duplicate, considering positive those superior to 20% of the difference between total and basal histamine. We have not observed any significant descent of the FEV1 with benzoate and salicylate in our group of 62 patients with ASA-triad, nor any manifestations presented with sodium metabisulfite, sodium nitrate and sorbic acid.(ABSTRACT TRUNCATED AT 250 WORDS)