The basic functional respiratory indices were followed up in 50 patients suffering from various forms of chronic obstructive pulmonary disease before and after treatment. A decrease of the dynamic indices followed up was found: inspiration indices--FEV 1% (forced expiratory volume), FVC% (forced vital capacity), FEV 1/FVC%, FEV 1/VC%; flow indices--MEF 25% (maximal expiratory flow), MEF 50% MEF 75%, PEF% (peak expiratory flow), MEF/FVC%, MMEF 25-70% (maximal mean expiratory flow). A decrease of vital capacity and of diffusion capacity was also found. The ratio RV/TLC% (residual volume/total lung capacity) was increased and a general hyperventilation was established. Moderate hypoxemia and lowered saturation by normocapnia and normal pH were also established. The control examinations after treatment showed improvement of all indices followed up.