Mushrooms have a great potential for the production of useful bioactive metabolites and they are a prolific resource for drugs. The spectrum of pharmacological activities of mushrooms is fascinating. Edible mushrooms are consumed by humans for their nutritional and occasionally medical value. The genus Pleurotus comprises some most popular edible mushrooms due to their favorable organoleptic and medicinal properties, vigorous growth and undemanding cultivation techniques. Pleurotus sp are now widely consumed as food in the East and increasingly in the West. Isolation and purification of polysaccharides from this mushroom fruiting body is relatively simple and straight forward and can be carried out with minimal effort. This book gives an insight into the isolation of polysaccharides and their significant antimicrobial and anti-oxidant activities. Results like these herald an interesting promise of constructing potentially active pharmacological agents from this mushroom.