A PROBLEM of growing importance in aviation medicine is one concerned with the treatment of acute aero-otitis media. The increasing volume of passenger traffic has resulted in a higher incidence of this condition. The precautions taken by military aviation personnel are not observed in commercial aviation. The risk of flying with infections of the upper respiratory tract is not realized by the average civilian passenger. In the seasoned flight passenger the press of business often occasions a disregard of this risk. This combination of factors is producing the higher incidence of acute aero-otitis media in commercial aviation. Acute aero-otitis media was frequently observed in military flying personnel during World War II. It was one of the most common causes of discomfort among flying personnel. Aero-otitis media is an acute or chronic traumatic inflammation of the tympanum caused by a difference of pressure between the air in the middle ear and