In 32 patients with relapsing bronchopneumonia, bronchiectasis, relapsing obstructive bronchitis and asthma bronchiale during aimed bronchoscopy bronchoalveolar lavage was made (BAL). The authors found typical cytological findings and deviations in the phosphatidyl choline level which is the main constituent of the pulmonary surfactant. The authors evaluated the importance of the surfactant for the proper function of the lungs and outlined possible therapeutic measures which by the action of some drugs will influence its formation.