Pleurotus ostreatus is a macrofungus that is a member of the family Pleurotaceae and class Basidiomycetes. It is also known as an oyster mushroom. It is the most significant mushroom that is grown for commerce. Numerous important nutrients and medicinal bioactive substances are thought to be present in this mushroom. It is rich in nutrients such as carbohydrates, proteins, fats, minerals, vitamins and volatile oil. It is used as food. It has a long history of usage as a medicine for many illnesses. It contains bioactive compounds such as alkaloids, saponin, phenolic compounds, glucans, quinones, triterpenoids, steroids, flavonoids, etc. It has been demonstrated that oyster mushroom possesses a variety of medicinal benefits. This review describes the immunomodulation, anticancer, antiplasmodial, antimicrobial, antihypercholesterolemic, anti-oxidant, anti-inflammation, atherosclerosis, antihyperglycemic and hypolipidemic activities of the oyster mushroom. These investigations will spark interest in Pleurotus ostreatus and may aid in the creation of a novel response for further investigation.