Objective To investigate the clinical significance of serum kynurenine(KYN) and Kynurenine 3-Monooxygenase(KMO) in schizophrenia(SZ) by determining them in SZ patients and healthy controls(CTR). Methods The concentration of KYN and KMO in serum of SZ patients and CTR were measured by enzyme linked immunosorbent assay(ELISA) and the KYN/KMO ratios were calculated. Results The KYN level in SZ patients were significantly higher than that in CTR, the KMO level in SZ patients were lower than that in CTR with significant difference, the concentration of KMO in male SZ patients and CTR were significa...