Background Previous studies have shown that chronic inflammation and oxidative stress may play an important role in the pathophysiology of polycystic ovary syndrome (PCOS), and glutamine (Gln) showed the anti-inflammatory and antioxidant properties. So the aim of this study is to investigate the effect of glutamine supplementation on PCOS rats. Methods Female Sprague–Dawley rats were randomly assigned into five groups (n = 10 /group), control group, PCOS group, PCOS+0.5g/kg Gln group, PCOS+0.75g/kg Gln group and PCOS+1.0g/kg Gln group. All the PCOS rats were administrated with 6 mg/100 g dehydroepiandrosterone (DHEA) for 20 consecutive days, all the PCOS+Gln groups were intraperitoneal injected Gln twice in the next morning after the last DHEA injection. All the samples were collected 12 hours after the last administration. Ovarian histological examinations were analyzed and the concentration of serum hormone, inflammatory and oxidative stress factors were measured. Results There was no obvious ovarian histological change among the PCOS group and PCOS+Gln groups. All the detected inflammation factors (IL-6, IL-18, TNF-α and CRP) showed significantly higher in all the PCOS groups compared to the control group (P<0.01), and were significantly decreased with the low supplementation of glutamine (P<0.01, include 0.5g/kg group and 0.75g/kg group).Concentrations of SOD were significantly lower in all the PCOS groups (P<0.01) compared to the control group, and increased significantly with the low supplementation of glutamine (P<0.01, include 0.5g/kg group and 0.75g/kg group). Serum concentrations of MDA, NO and NOS were significantly higher in PCOS group (P<0.01) compared with the control group, and significantly decreased to the comparative levels of control group with the low supplementation of glutamine (P<0.01, include 0.5g/kg group and 0.75g/kg group). Conclusion There is low-grade inflammation and oxidative stress in DHEA-induced PCOS rats. The supplementation of glutamine with doses of 0.5g/kg and 0.75g/kg could effectively ameliorate the inflammatory and oxidative stress conditions of PCOS.