['To highlight the understanding of pulmonary embolism(PE), and analyze the trends of underline diseases of PE from Peking Union Medical College(PUMC) Hospital in the last half century.', '239 cases of PE were reviewed retrospectively from 1950 to 2000 in PUMC Hospital.', 'In the first and second periods (1950-1982, 1983-1990), about 3 cases of PE were diagnosed annually, but in the third (1991-1997) and fourth periods (1998-2000), 8 cases and 20.6 cases of PE were found annually. The incidence of underline diseases of PE, such as deep venous thrombosis (DVT), cardiac disease, malignancy and connective tissue disease varied in different periods. The morbidity of DVT with PE was dramatically enhanced recently.'] Do [ Trends of underline diseases of pulmonary embolism from Peking Union Medical College Hospital ]?