Objective To study the antagonistic effect of organic extracts of Fruit of Chinese Wolfberry (FCW) on chromium (Ⅵ) _induced mutation. Methods Using unscheduled DNA synthesis (UDS) assay, the effects of 0.02 g/ml, 0.01 g/ml and 0.005 g/ml organic extracts of FCW on UDS induced by potassium bichromate [0.31 ?g/ml Chromuim (Ⅵ)] in human peripheral blood lymphocytes were determined. The effects of the order of adding organic extract of FCW and potassium bichromate into cultured lymphocyte suspension on UDS were observed at the same time. Results The value of CPM revealed a significantly higher level in positive control group exposed to 0.31 ?g/ml chromium (Ⅵ) compared with that in negative control group exposed to disstilled water (P