Objective To explore the difference of youth between old people's single side pleural effusionpathogeny distributing between the young and the old. Methods Collecting the patients from Jan. 1996 to Aug.2004 and dividing them into two groups, the young group and the old people group, and comparing them. ResultsThe percentage of every illness types in young group: tuberculosis 79.1%, cancer 4.7%. The percentage of everyillness types in the old group: cancer 59.3% tuberculosis 20.4%.The difference between the ...