Sun Ten – Siler & Astragalus Formula Granules / Yu Ping Feng San / 玉屏風散. Yu Ping Feng San, also known as Astragalus and Siler Formula or Jade Windscreen Powder is used to support immune system. Ingredients: Fang-feng root (fang feng), Astragalus root (huang qi), Atractylodes root (bai zhu), Ginger (Fresh) (sheng jiang), Jujube (da zao).