132 bronchial asthma patients living in Frunze (760 m above the sea level) and those on adaptation days 3-5 and 25-30 to the climate of North Tien Shan (3200 m above the sea level) underwent clinical and functional examination involving assessment of ACTH, cortisol and aldosterone levels. The patients showed clinical response and improvement of bronchial permeability associated with a pronounced growth of plasma cortisol levels starting on adaptation days 3-5. By adaptation days 25-30 cortisol levels were still on the increase while ACTH concentration tended to reduction.