SummaryRecently treatment with aerosol inhalation has yielded interesting results.By this method it is possible to reach satisfactory blood concentrations. However what seems to be its most interesting effect is the local action of the pulverized drugs on the respiratory tract.Good results have been obtained in penicillin aerosol treatment of cases with bronchiectasis: in preparation and after-treatment of cases in which surgery could not be performed.Other diseases have been treated: infections of the upper respiratory tract, pneumonia. Special mention is due to the treatment of cases with lung-abces and bronchial asthma.