SummaryWhereas the clinical data of the history guided the diagnosis only in 26 % of the cases, skintesting systematically used in 200 cases of breathdiseases supposed to be allergic allowed etiologic diagnosis in 75 % of the cases.It is house-dust that plays the main part, as well for their frequency (70 %) as for the seriousness of the crisis and their appearance during the whole year.The grass-pollens occur in 20 % of the cases but in 5 % only alone.The other allergens (inhaled or ingested) that give positive skin reactions are detailed and discussed. They are always associated with dust or pollens except for one case.