A Viscum coloratum lectin (VCL) was first separated from extracts of the stems and leaves of Viscum coloratum Chinese,an ordinary traditional medicine beijisheng,by affinity chromatography on acid-treated Sepharose 6B and gel filtration on Sephacryl S-200,with Mr=52 000,pI=10.5.The LD₅₀ was 4.4μg/kg for mice by intravenous injection,It's a toxic protein obtained from the plant with higher toxicity to mice. The crude extracts of the poant also have strong toxicity,because it's LD₅₀ was 200 mg/kg for mice by intraperitoneal injection and to be expressed as the amount of dry materials.