Abstract: Objective To study the effect on supplying antioxidants to reduce hepatic and renal toxicity during pretreatment in hemopoietic stem cell transplantation. Methods 100 patients were randomly divided into 2 groups by single blind design. The test group was given Vit C (300 mg/d) and Vit E (600 mg/d) 15 days Before the pretreatment and the control group was given nothing. Other interventions were the same. The ALT，BUN，Cr and TAC，MDA were detected before and after HSCT. Results Significant differerces of the TAC，MDA，ALT，BUN and Cr between the two groups after HSCT. Conclusion Supplying antioxidant vitamins before pretreatment improved the antioxidant capacity and reduced lipid peroxidation of HSCT patients, and helped to control the hepatic and renal toxicity from pretreatment efficiently.

Key words: hemopoietic stem cell, free radical, antioxidant, multiple organ failure/complication