The β-glucan active structure is a polysaccharide composed of glucose units, most of which bind through β-1,3, which is the manner in which the glucose chains are linked. It can activate macrophages, neutrophils, etc., thus increasing the levels of leukocytes, cytokinins and specific antibodies, and fully stimulating the body's immune system. Then, the body has more preparations to fight the diseases caused by microorganisms. Β-glucan can quickly restore the normal ability of lymphocytes in the body to produce cytokines (IL-1), and effectively regulate the body's immune function. A large number of experiments have shown that β-glucan can promote the production of IgM antibodies in vivo to improve the immunity of body fluids. This glucan-activated cell stimulates the host's non-specific defense mechanism, so it has attracted much attention in tumors, infectious diseases, and treatment of wounds. Beta-1,3 glucan extracted by special steps and without endotoxin has been identified as a safe substance in the US FDA and can be added to general foods. Many reports show that mice are orally administered yeast β-1,3 glucan. It can increase the anti-phagocytic effect of strong peritoneal cells. In addition, dextran has the ability to scavenge free radicals, resist radiation, dissolve cholesterol, prevent hyperlipidemia and resist infections caused by viral viruses, fungi, bacteria, etc. Therefore, it is widely used in medicine, food, cosmetics and other industries. Nowadays, yeast glucan has been industrialized.