In the field of respiratory diseases during aging, obstructive diseases hold a prominent position because they are frequent and are potentially "tractable" and thus subjected to careful therapeutic intervention. Bronchial asthma and chronic obstructive pulmonary disease are most important clinical patterns. Bronchial asthma (in chronic and in uncommon, newly diagnosed, forms) in the elderly are more frequent than commonly known. Wider and deeper studies of chronic obstructive pulmonary disease, besides, have demonstrated that a component of reversibility is present even in the older patients, in a ratio of 20-40%. The reversible bronchial obstruction appears therefore, in the older patients, as a qualitatively and quantitatively important event, in the clinical and therapeutical field. The recent production of international Guidelines (ATS/ERS, 1995) gives the possibility--for this type of diseases--of utilizing more accurate diagnostic criteria and new therapeutic approaches.