目的探讨重型腹泻时患儿脂质过氧化反应在病变过程中的作用及应用大剂量维生素Ｃ抗氧化治疗的效果。方法对５岁以下重型腹泻患儿，应用大剂量维生素Ｃ前及后１小时测红细胞超氧化物歧化酶（ＳＯＤ·Ｈｂ）活性及血浆脂质过氧化分解产物丙二醛（ＭＤＡ）含量进行动态监测并与健康儿童作对照观察。分别采用黄嘌呤氧化酶法及硫代巴比妥酸比色法测定。结果重型腹泻患儿发病期ＳＯＤ·Ｈｂ活性明显低于健康儿童，血浆ＭＤＡ含量明显高于健康儿童（Ｐ＜０００１）；重型腹泻患儿大剂量维生素Ｃ治疗后１小时与治疗前相比ＳＯＤ·Ｈｂ活性明显升高（Ｐ＜００１）。血浆ＭＤＡ含量明显降低（Ｐ＜００１）。结论重型腹泻患儿病变过程中存在自由基损伤，大剂量维生素Ｃ能单独、迅速、有效地清除自由基，且能保护自身抗氧化功能 Objective To investigate the role of lipid peroxidation in children with severe diarrhea and the effect of high-dose vitamin C antioxidant therapy. Methods In children with severe diarrhea under 5 years of age, the activity of SOD · Hb and the content of malondialdehyde (MDA) in plasma lipoperoxidase were measured before and after high dose of vitamin C Monitor and monitor with healthy children. Respectively, using xanthine oxidase method and thiobarbituric acid colorimetric determination. Results The onset of severe diarrhea in children with SOD · Hb activity was significantly lower than healthy children, plasma MDA levels were significantly higher than healthy children (P <0001); children with severe diarrhea 1 hour after treatment with high-dose vitamin C compared with before treatment SOD · Hb activity was significantly increased (P <0  01). Plasma MDA levels were significantly lower (P <001). Conclusion There is free radical damage in children with severe diarrhea. High-dose vitamin C can scavenge free radicals rapidly, effectively and protects their anti-oxidant function