Mushrooms and their extracts including purified ingredients, are currently used as foods, functional foods (and/or nutraceuticals), and medicines. These products have numerous bioactive compounds such as polysaccharides (mainly β–glucans), glycoproteins, nucleotide analogs, terpenoids, and polyphenols, which have exhibited antioxidant, antimicrobial, anticancer, antiviral, anti-obesity, and immunomodulatory activities. In this review, we discuss the current information on the biactivities of 10 popular mushrooms in Korea. We also summarize the information on mushrooms and the active compounds derived from them, as well as mushroom-based products such as foods, functional foods, and medicines. We believe this review could provide useful information for scientists and consumers who seek to develop new products and promote healthy food habits and lifestyle.