Abstract: After being soaked in aluminium citrate,mixed rare earths or sodium selenite soultions at different concentrations for 1 hour,chrysotile were incubated with human embryo lung(HEL) cells.Then,the superoxide anion(O₂^-)in the culture medium were determined.The results showed that chrysotile caused increase of O₂^- in the culture medium,but the three compounds pretreated chrysotile induced less O₂^- production than the native chrysotile.These results indicated that the pretreatment of chrysotile with three compounds can inhibite the chrysotile induced O₂^- production in HEL cells.