The acute bronchospasmolytic effect of nitroglycerin was clinically and experimentally tested and confirmed in 92 patients with chronic obstructive bronchopneumopathies. It is longer provable than the cardiocirculatory and haemodynamic effect, respectively, of nitroglycerin and in its intensiveness depends on the initial value, the degree of bronchial obstruction. The average increase of the ventilation parameters FEV1 and FVK achieved by the perlinqual application of 0.4 mg nitroglycerin during the first thirty minutes corresponds approximately to the broncholytic effect of 0.6 mg inhalatively given isoprenalin. In comparison with the efficacy of adrenalin, alupent, ephedrine, euphyllin, methyl ephedrine, prednisolone and papaverin, which were controlled during 2 hours and graduated in its succession, at the end of the test a "lower" mean position between euphyllin and methyl ephedrine belongs to nitroglycerin. Concerning the frequency of positive tests nitroglycerin is to equalize to prednisolone and methyl ephedrine and more favourable than papaverin.