The origin, course, diagnosis and treatment aspects of acute pneumonia have been studied in 394 patients with chronic bronchitis and 158 bronchial asthmatics. In chronic bronchitis, acute pneumonia was diagnosed resting on clinical physical data in one-third of the patients, the rest cases simulated exacerbations of bronchitis and were detected only at x-ray. Clinical relationships between acute pneumonia and bronchial asthma are variable (prepneumonic asthma aggravation , its early and late severe episodes because of pneumonia). Chronics with nonspecific diseases of the lungs are referred to high-risk-for-pneumonia groups, while acute pneumonias are considered affections negatively influencing background bronchopulmonary disorders.