The entire mushroom may be consumed. It is a culinary staple in many Asian cultures. As dietary supplement, Shiitake mushroom is frequently used to support the immune system.. Lentinan , a polysaccharide, is believed to be the active component and has been studied extensively in Japan.

Lentinan, lignins, 1-3-beta-D-glucan, linoleic acid, ergosterol, lysine, arginine, methionine, phenylalanine, potassium, calcium, magnesium, manganese, iron, copper, and zinc.