Maitake mushroom (Grifola frondosa) is an edible, medicinal mushroom. It has been extensively studied for the past 30 years, revealing numberous medicinal properties that could provide great health benefits. Those include various physiological benefits ranging from immunomodulatory and antitumor activities to treatment for diabetes, hypertension, hypercholesterolemia, viral infections (hepatitis B and human immunodeficiency virus), called “maitake D-fraction” and “maitake SX-fraction”. A number of scientific studies have been performed on these two maitake derivatives, which are thus well characterized. Maitake D-fraction consists of proteoglucan (protein-bound polysaccharide), or more specifically known as Beta-glucan. This Beta-glucan is an active component of D-fraction and its two major biological activities, immunomodulatory and antitumor, have been the main target for scientific and clinical research