Main effects: the contents of amino acids and trace elements are higher than those of domestic American ginseng and wild ginseng; Taurine and its polysaccharide have the functions of nutrition, anti-aging, nourishing and protecting liver and regulating human immunity. Dendrobium candidum (scientific name: Dendrobium officinale Kimura et migo), also known as black knot grass and Yunnan iron sheet. It belongs to Orchidaceae perennial epiphytic herb Microsuborder. The stem is upright, cylindrical, 9-35 cm long and 2-4-5 mm thick. Sepals and petals are yellowish green, nearly similar, oblong-lanceolate, about 65438 0.8 cm long and 4-5 mm wide. The flowering period is from March to June. Mainly distributed in Anhui, Zhejiang, Fujian and other places in China. [ 1]? Its stem is used as medicine, which belongs to tonic medicine: benefiting stomach, promoting fluid production, nourishing yin and clearing heat.