OBJECTIVE:To investigate the effects of UGT1A6 and UGT1A9 gene polymorphisms on blood concentration of valproic acid in Han epileptic patients.METHODS:Totally 107 Chinese Han epileptic patients were selected from outpatient department of our hospital during Jan.2014-Apr.2015.They were given valproic acid monotherapy treatment for 3 months to 6 years.The steady state concentration ofvalproic acid was detected by EMIT.UGT1A6 (rs2070959,rs6759892) and UGT1A9 (rs13418420,rs2741045,rs2741049,rs6731242,rs72551330) genotypes were detected by MALDI-TOF-MS.The correlation of gene polymorphism with con centration dose ratios (CDR) of valproic acid was investigated.RESULTS:UGT1A9 rs72551330 mutation had not been detected,and the frequency of genotypes in other 6 sites were all in line with Hardy-Weinberg balance (P＞0.05).The CDR of valproic acid in pa tients with UGT1A6 rs2070959,rs6759892 mutation (AG+GG or TG+GG type) were significantly lower than those with wild homozy gote (AA or TT type),with statistical significance (P＜ 0.05).There was no statistical significance in CDR of valproic acid among patients with UGT1A9 rs13418420,rs2741045,rs2741049 and rs6731242 wild homozygote and mutation (P＞0.05).CONCLUSIONS:UGT1A6 rs2070959,rs6759892 gene polymorphisms of Han epileptic patients are associated with blood concentration of valproic acid,and the patients with UGT1A6 rs2070959,rs6759892 mutation need more dose ofvalproic acid.