Given the evidence that MTHFR genotypes potentially affect the metabolic profiles in patients with schizophrenia treated with antipsychotics, and that the effects may be related to low folate levels and may differ among different ethnicities, we explored the associations of MTHFR genetic variants and serum folate level with metabolic parameters in patients with schizophrenia treated with antipsychotics in the Han Chinese population in Taiwan. The gene discussed is MTHFR; the disease is schizophrenia.