The value of the allergen extract, Aquagen SQ-Dpt, for performance of the bronchial provocation test in allergic asthma patients was evaluated. The studies were carried out on 117 patients suffering from allergic mite asthma. Bronchial challenge was performed according to Ryan's method. After an allergen inhalation, an early asthmatic reaction (EAR) and a late asthmatic reaction (LAR) may appear. In our studies a dual reaction (EAR and LAR) was observed in 53.8% of the patients, the EAR only in 27.4% and the LAR only in 2 patients. The subjects with the dual response demonstrated a higher sensitivity to the allergen than those with only the EAR. A positive, statistically significant correlation between specific and non-specific bronchial hyperreactivity was found. The frequency of the appearance particular patterns of the bronchial responses was similar to those published by other authors, using different allergen extracts. Aquagen SQ-Dpt can be used to perform of the sBPT.