Oyster mushrooms are popular edible mushrooms and commercially available in Korea and Bangladesh, which has been widely used for nutritional and medicinal purposes. The sequences of ITS region of selected strains revealed that the total length ranged from 507 to 663 bp. Sequence analysis showed that 5.8S of rDNA sequences were identical. RAPD and ITS techniques were well competent for detecting the genetic diversity of all tested strains of oyster mushrooms. Evaluation of the antioxidant activities, tyrosinase inhibitory effects on the fruiting bodies of oyster mushrooms extracted with acetone, methanol and hot water. Feeding of a diet containing a 5% P. citrinopileatus, P. eryngii, P. nebrodensis, P. ostreatus, and P. salmoneostramineus fruiting bodies to hypercholesterolemic rats reduced plasma total cholesterol, triglyceride, LDL, total lipid, phospholipids, and LDL/high- density lipoprotein ratio. Feeding mushroom also significantly reduced body weight in hypercholesterolemic rats. The plasma lipoprotein fraction, separated by agarose gel electrophoresis, indicated that oyster mushroom significantly reduced plasma ¿ and pre-¿- lipoprotein, while increased ¿-lipoprotein.