Abstract: It has been reported in the previous paper the composition of Chinese mistletoe "Pei-Chi-Sheng" (Viscum albiun L. var. coloration Kom.) . The chemical consti- tuents in South China mistletoe "Kwang-Chi-Sheng" Loranthus paraciticus L. (Merr.) has been investigated in the present work. Two kinds of crystalline substances have been isolated: one kind of pale yellow needles, m.p. 214-215℃, C₂₀H₁₈O₁₁, yield 0.4%, and the other golden yellow needles, m.p. 310-313℃, C₁₅H₁₀O₇, yield 0.02%. The former was identified as quercetin-3-arabinoside, which has the same chemical structural formula as "Avicularin" (From polygonum aviculare L.). It is, how- ever, the first time to discover the compound in Loranthus L. The arabinoside is a powerful diuretic. The second compound was quercetin which was identified by its acetylated and exhaustive-methylated products.