Astragalus Root - The historical use of astragalus for immune support has been backed up by studies suggesting that it may help maintain healthy white blood cell and interferon activity.Elderberry Fruit - Research highlighting a potential value in supporting immune function in influenza sufferers have made elderberry one of the most popular resistance supplements. The impressive flavonoid profile is especially worth noting in this respect.Garlic Bulb - Numerous studies have demonstrated that the sulphur compounds in garlic are active against a wide range of harmful microbes. This evidence supports the historical use of garlic in maintaining healthy resistance.Oregon Grape Root - Oregon grape root is abundant in constituents with research-proven activity against a vast array of pathogens. There is also a suggestion that this root may support convalescence after certain types of infections.Osha Root - Osha has been historically used for maintaining the health of the respiratory tract and mucous membranes. Compounds in osha also appear to possess activity against certain microbes. Osha is often reported to encourage perspiration, which also may account for some of its value in supporting resistance.Maitake Mushroom Mycelia - Beta glucans, a group of polysaccharide compounds prevalent in maitake mycelia, have been the subject of numerous studies highlighting remarkable immune supportive properties. Although this polysaccharide group is abundant in certain other species of fungi and plants, maitake beta glucans are possibly the most heavily researched to date.