Planetary Herbals Astragalus Jade Screen is a classic Chinese herbal formula (Yu Ping Feng Wan), which combines premium-grade Astragalus membranaceus with the Chinese tonics, atractylodes and siler. This is one of the most relied-upon formulas in Chinese herbalism to strengthen immune resistance. The ancient texts say this preparation will 'protect you from the cold winds as if surrounded by a screen of jade.' Modern research has confirmed the use of astragalus to support immune defenses and enhance macrophage activity.