Beta-glucan (Imucell WGP) is an over-the-counter dietary supplement that enhances the body's immune system. Imucell WGP is extracted from food-grade baker's yeast, which is permitted for use in food by the U.S. Food and Drug Administration (FDA). Studies in animals have shown that Imucell WGP helps trigger white blood cells to destroy cancer cells. Other animal studies combining Imucell WGP with anti-cancer medications have shown greater tumor regression and tumor-free survival.