The Authors studied lung mechanics, acid-base balance parameters, arterial blood pressure and pulse rate in five different groups of chronic obstructive lung disease patients, undergoing e.v. different bronchodilators. The drug were: 1. group: 500 gamma of orciprenalina; 2. group: 500 gamma of idrossi-fenil-orciprenalina; 3. group: 200 gamma of salbutamolo; 4. group: 100 gamma of trimetochinolo; 5. group: 500 gamma of terbutalina. The comparative analysis of bronchodilators, their cardiovascular effects and on acid-base balance indicate that mainly salbutamol and trimetochinol have negligeable adverse effects.