The alfa1-antitrypsin level was followed up in patients with bronchial asthma with different forms and severity of the disease. The latter was found to be elevated in all patient groups with an average of 335,38 mg% as compared with the controls 290.83 mg%, p less than 0,01. The elevated antitrypsin is explained with the allergic process and the secondary bacterial inflammatory reactions, triggering the formation of antienzyme substances, in order to inactivate the enzymes, playing a certain role in the pathogenesis of the first two processes--allergy and bacterial inflammation. In patients, both treated and not with cortisone, antitrypsin is elevated with no manifestation of significant difference for both patient groups. The cortisone preparations very likely do not supress the antienzyme systems in organism. As regards the pathogenetic role of alfa1-antitrypsin deficiency in asthma, the latter is admitted to play an insignificant role only in single cases.