Nutritional supplement formulated with concentrated extract of maitake (Grifola frondosa), concentrated extract of shiitake (Lentinus edodes) and Beta-1,3/1,6-glucans. The composition stimulates the body's natural defences. Beta-glucans are components of the membranes of several medicinal mushrooms, including shiitake and maïtake. Numerous studies have shown immunostimulant effects during the winter and in case of fatigue.