Edible mushroom that I choose is grey oyster mushroom. Grey oyster mushroom (Pleurotus sajor-caju) belongs to Class Basidiomycetes and in Agaricaceae family. In Malaysia, grey oyster mushroom was among the popular edible mushroom. This edible mushroom famous in Malaysia because it is very suitable in our lowland area. It is grow easily in our tropical forests as they grows on dead and decaying wooden logs or sometimes on dying trunks of deciduous or coniferous woods. It is also can grow naturally in our temperature.Mushroom have their own economic important as mushroom have a higher demand from the local and international markets due to their uniqueness from every single characteristic. From the last three decades, mushroom shows a significant upward trend in global trade. Malaysia also not excluded from this phenomenon. This is shown by their contribution on gross national income. It is required about 50 tonnes of mushroom per day to fulfil the demand in this local market. But our current production is only about 24 tonnes per day. Therefore, it is selected as one of the seven commodities that can be develop commercially to generate higher income for the farmers and the country. Mushroom that been sold in our market was divided into three categories which is fresh, dried and mushroom based product.As the time goes by, our Malaysian people getting more educate towards finding healthy food and alternative medicine to protect themselves from illness rather than consume hospital medicine and they discover that mushroom give so much benefits and contain a lot of nutrient which did not harm them. This make the demand for mushroom increases. In economic and technology management review, Vol 9b (2014): 103-111, they stated the demand is estimated to increase from 20,000 tonnes in 2008 to 48,000 tonnes in 2020.On the other side, demand for the mushroom for international markets also increases make Malaysia have high opportunity to develop their mushroom industries and lead to contribute in our gross national income. As shown in the table above, our supply toward international markets is still at low level. We only can export around 500 to 2000 tonnes of mushroom per year. Meanwhile, China can export more than 30,000 tonnes of mushroom per year. This prove can make us improve our mushroom cultivation to fulfil the international market demand. It is clearly shown that mushroom was very importance in our economic.Among all the cultivated edible mushrooms, Pleurotus species are known as the cheapest and easiest to grow. Compared to button mushroom cultivation method, grey oyster mushroom cultivation only required simple method which does not require complicated substrate preparation technique. It can be grown on non-fermented, almost fresh plant residues (agri-wastes containing lignin and cellulose). Furthermore, grey oyster mushroom can grow at moderate temperature ranging from 20 to 300 C and humidity 55-70% for a period of 6 to 8 months in a year. Substrate preparation does not require controlled environmental conditions as in case of button mushroom. It can also be cultivated in summer months by providing the extra humidity required for its growth. In hilly areas above 900m. (m.s.l.), the best growing season is during March/April to September/October and in the lower regions from September/October to March/April. It’s also grows on decay organic matter which make it easy to be grows for commercial. This is the best mothed been used by farmers that run the commercial business either to fulfil the domestic demand or international demand towards grey oyster. Unlike white button mushroom, the oyster mushroom fruit bodies can be easily dried and stored. Dried oyster mushrooms can be instantly used after soaking in hot water for 5 to 10 minutes or it can be used in powdered form for several preparations. Fresh mushrooms have a shelf life of 24-48 h even at room temperature.Mushroom species have the potential to be developed into functional foods for their high nutritional value and because they are a source of biologically active compounds of medicinal importance. The investigation on the beneficial properties of edible mushrooms has gained attention by the scientific community during the last decades. In the light of the emerging literature, the objective of this review was to compile the more recent information about the health benefits associated to the edible mushrooms intake. It can be concluded that the consumption of mushrooms as a part of daily diet could be a natural adjuvant for the treatment and prevention of several chronic diseases.The economic importance of the grey oyster mushroom first of all it is use as food for human consumption. It is rich in Vitamin C and B complex. This oyster mushroom have the protein content varies between 1.6 to 2.5 percent which mean it has most of the mineral salts that required by the human body. This mushroom act as an alternative source of protein to poor people in the developing country to be consume as it is contain all the nine essential amino acids which basically needed for human growth. Grey oyster mushroom have high demand from end users. As it offer affordable price to be consume as a daily food intake. It is also good for the non-vegetarian as they can replace the protein from meat just by eat mushroom. The niacin content is about ten times higher than any other vegetables. The niacin is used to Oyster mushrooms also serve as a source of niacin, or vitamin B-3. Like iron, niacin supports your metabolism. It helps you break down nutrients — including the carbohydrates, proteins, fats and alcohols from your diet — into fuel for your tissues. Niacin also regulates the activity of G-proteins, a class of enzymes involved in cell communication. Each 1-cup serving of oyster mushrooms provides 4.3 milligrams of niacin, which is 31 percent of the recommended daily intake for women and 27 percent for men, according to guidelines set by the Institute of Medicine. On the other side, oyster mushroom contain folic acid which can helps to cure anemia that usually attack pregnant women as they give their nutrient to their baby. For people whom have hyper-tension, obesity, and diabetes they also can eat this oyster mushroom as its low sodium : potassium ratio, starch, fat and calorific value. It is also suitable for those having hyperacidity and constipation as it have alkaline ash and high fibre. As the conclusion, grey oyster mushroom have its own economic importance. It is contribute to gross national income because it have high demand on domestic and international markets which increases up to 15% every single year.