OBJECTIVE:To discuss the effects of cyclosporine combined with methylprednisolone sodium succinate pulse thera-py on pulmonary fibrosis in patients with acute paraquat poisoning. METHODS:By retrospective study method,39 cases of acute paraquat poisoning were divided into observation group(21 cases)and control group(18 cases)according to therapy plan. Control group received blocking the absorption of poison,promoting the discharge of poison’supportive and symptomatic treatment;obser-vation group was additionally given Methylprednisolone sodium succinate for injection 1 000 mg,ivgtt,qd+Cyclosporin injection 5 mg/kg,ivgtt,qd,pulse therapy;the dose of dethylprednisolone sodium succinate decreased gradually since forth day and it had been stopped after 7 days. The serum levels of hyaluronic acid(HA),laminin(LN),Ⅳ collagen(CⅣ),Ⅲ procollagen(PCⅢ), matrix metalloproteinase(MMP)9 and serum matrix metalloproteinase inhibitors(TIMP)1, lung HRCT score were observed in 2 groups,and the occurrence of ADR was recorded. RESULTS:HA and PCⅢ of observation group on 3rd and 5th day of treatment were significantly lower than those of control group,and HA,CⅣ and PCⅢ on 7th and 14th day of treatment were significantly lower than those of control group,levels of MMP-9 in observation group on 3rd,5th,7th day of treatment were significantly low-er than those of control group,with statistical significance (P<0.05). Levels of TIMP-1 and HRCT score in 2 groups increased gradually 2 weeks after treatment,and that of observation group was significantly lower than that of control group,with statistical significance (P<0.05). No obvious ADR was found in 2 groups during treatment. CONCLUSIONS:Cyclosporin combined with methylprednisolone sodium succinate pulse therapy can significantly relieve pulmonary fibrosis in patients with acute paraquat poi-soning with good safety.