It is found that plant oils except Beta-sitosterol have almost the same Carbon contents, approximately 77.50%, comparing carbon contents of various oils by elemental analyzers, which means it is not possible to classify mixed oils using only elemental analysis. In addition, sulphur is not detected. It is proved that various sterol compositions exist in pumpkin seed oil in result of High Performance Liquid Chromatography(HPLC), also showing same sterol contents between Italian and Chinese pumpkin seed oils. However, it is not detectable whether other kinds of adulteration oils are mixed in pumpkin seed oil. Recently, pumpkin seed oil extract is also applied in therapy of disorders of the prostate gland and the urinary bladder. The therapeutic use and safety of a pumpkin seed oil extract were investigated in a clinical study with 2245 paticents suffering from Benign Prostatic Hyperplasia. Evaluation of the study was accomplished according to the International-Prostate-Symptom-Score(I-PSS), which decreased by 41.4%, while live quality improved by 46.1% during the treatment.