Objective:To explore the effects of genotypes of one-carbon metabolism (OCM)-related enzyme single nucleotide polymorphisms (SNPs) sites and anti-epileptic drugs on OCM metabolite levels in epileptic patients, and to screen valproic acid (VPA) teratogenic susceptibility genes.Methods:Three hundred and seventy-two epileptic patients, admitted to our hospital from January 2019 to December 2020, were enrolled in the study; patients taking VPA, levetiracetam (LEV), lamotrigine (LTG) or oxcarbazepine (OXC) for more than 6 months without attack during regular medication were classified as VPA group ( n=95), LEV group ( n=61), LTG group ( n=57) and OXC group ( n=70); firstly diagnosed epileptic patients who had never taken antiepileptic drugs or had not taken antiepileptic drugs in the previous 6 months were assigned into blank control group ( n=89). Plasma folic acid (FA), vitamin B12 (VitB 12) and homocysteine (Hcy) levels were determined by automatic chemiluminescence immunoassay, and genotypes of OCM-related enzyme SNPs sites were detected by Sequenom iPLEX. Results:(1) As compared with LEV group and blank control group, VPA group had significantly decreased FA level and significantly increased Hcy level ( P<0.05). (2) Patients with DNA methyltransferase (DNMT) 3a rs12987326(-178G>A) GA type had significantly higher Hcy level than those with GG type ( P<0.05); patients with DNMT1 rs2288350(82G>C) GC type had significantly higher Hcy level than those with GG type ( P<0.05); patients with DNMT1 rs75616428 (55850G>C) GC type had significantly lower VitB 12 level than those with GG type ( P<0.05). Patients with DNMT1 rs1863771(128G>A) GA+AA type had significantly higher FA level than those with GG type, patients with folate receptor 2 rs2298444(59T>C) CT+CC type had significantly higher Hcy level than those with TT type, patients with 5,10-methylenetetrahydrofolate reductase rs1801131(1298A>C) AC+CC type had significantly higher Hcy level than those with AA type, and patients with DNMT3a rs6722613(2327C>T) CT+TT type had significantly lower VitB 12 level than those with CC type ( P<0.05). Conclusions:Decreased FA and increased Hcy levels can be noted in epileptic patients who used VPA; some gene variations in SNPs of OCM also affect the OCM metabolite levels in epileptic patients. Epileptic patients during pregnancy should avoid using VPA or detecting SNPs genotypes before medication to reduce the incidence of fetal malformation.