Passive smoking is the involuntary inhalation of tobacco smoke by a person, especially a non-smoker, who occupies and area with smokers or a smoker. Passive smoking may cause eye and nose irritation, sore throat, headache, cough to everyone, and it is known that non-smokers have the same kinds of illness with smokers. Smoking rate among the adults aged over 20 in Korea is higher than that of the US or European conturies. Therefore we suppose that Koreans may be exposured to passive smoking than the people of other conturies. It is necessary that people have the knowledge on the heath problems caused by passive smoking and on prevention from the involuntary inhalation of tobacco smoke. I propose that the smokers should be informed the importance of smoking cessation.