Ganoderma lucidum comprises probably 400 different biologically active constituents principally polysaccharides, triterpenoids, proteins, enzymes, steroids, sterols, nucleotides, fatty acids, vitamins and minerals which have been proved to have several therapeutical properties to control various diseases. Broad spectrum of its pharmacological actions have been established which include immunomodulation, anticancer, antidiabetic, antioxidant, antiatherosclerotic, antifibrotic, chemopreventive, antitumor, anticancer drug toxicity prevention, analgesic, anti inflammatory, antinociceptive, antimicrobial, hypolipidemic, hepatoprotective, antiandrogenic, antiangiogenic, antiherpetic, antiarthritic, antiosteoporotic, antiaging, antiulcer properties and estrogenic activity. The present review is an effort to investigate and compile the reported biologically active compounds, pharmacological activity, toxicity and comparative study of different medicinal mushrooms.