Beta glucans are sugars that are found in the cell walls of bacteria, fungi, yeasts, algae, lichens, and plants, such as oats and barley. They are sometimes used as medicine. Beta glucans are used for high cholesterol, diabetes, cancer, and HIV/AIDS. Beta glucans are also used to boost the immune system in people whose body defenses have been weakened by conditions such as chronic fatigue syndrome, or physical and emotional stress; or by treatments such as radiation or chemotherapy. Beta glucans are also used for colds (common cold), flu (influenza), H1N1 (swine) flu, allergies, hepatitis, Lyme disease, asthma, ear infections, aging, ulcerative colitis and Crohn's disease, fibromyalgia, rheumatoid arthritis, and multiple sclerosis.