Abstract: Using GC/MS to Determine Androgen in Urine of a Male in "PIGU" QIGONGLuo Chuanhuan; Wang Zuohua; Ma Chengyu (Institute of Radiation Medicine,27 Tai Ping Lu, Beijing 100850,China) Abstract:"PIGU" QIGONG is a kind of deep breathing exercise in Chinese traditional medicine, people can have no grain food but drink water and take some fruits for a long time. A man, Mr. Wang, has been practising "PIGU" for a month under medical care conditions. During this period, dihydrotestosterone, testosterone and androstenedione in his urine were determined using GC/MS with dehydrotestosterone as internal standard. The results show that androgen in urine was decreased during this period ; the decreasing rate of androgen level slows down gradually and the level of testosterone is the lowest among three androgens, then, dihydrotestosterone and androstenedione. Keywords: "PIGU" QIGONG, Anerogen, GC/MS, ISTD