This study evaluated the mechanisms of 5-fluorouracil （5-FU） induced intestinal damage by investi-gating the lipid peroxide （LPO） level

myeloperoxidase （MPO） activity and disaccharidase activity in rats.Group Ⅰ animals （n=6） were sacrificed and served as a normal control group. Group Ⅱ animaIes （n= 24 ）were given a single intraperitoneal injection of 5-FU （150 mg/kg） and every 8 rats were sacrificed on day1

3 and 5 after injection respectively. Results: LPO concentration in blood and intestinal mucosa was sig-nificantly higher in the group Ⅱ than in the group Ⅰ on day 1 and 3 （P<0. 05） MPO activity was signif-icantly higher in the group I than in the group Ⅰ at different times （P<0. 01 ）. Lactase activity on day 5（P<0. 01）; sucrase activity （P<0. 01 and P<0. 05 respectiviely） and maltase activity （P<0. 01 ） on day3 and 5

were significantly lower in the group than in the group l. Conclusion: The results indicatethat neutrophil infiltration may be involved in 5-FU-induced lipid peroxidative damage of the small intes-tine which was reflected by the decreased disaccharidases activities.