Background and Objectives: One of the most common complications after childbirth is postpartum depression (PPD), a major depressive disorder. The aim of this study was to investigate the effects of the hydroalcoholic extract and oil of Quercus brantii as an experimental model of PPD in rats. 
Subjects and Methods: 42 adult female Wistar rats in six groups were used in this study. All animals received daily progesterone injections at a dose of 5 mg/kg intraperitoneally for 5 consecutive days. A hydroalcoholic extract of Quercus brantii (100mg/kg) and oil (45%) were administered simultaneously with PPD modeling by progesterone withdrawal. On day 8, depressive behavior was then assessed by a forced swim test. To investigate the role of the oxidant-antioxidant system, reduced glutathione (GSH), catalase, superoxide dismutase (SOD) and malondialdehyde (MDA) have been assessed after the last injection. 
Results: Statistical analysis showed that progesterone induced significant immobilization in the control group receiving saline (P<0.001) and in the vehicle group receiving sesame oil (P<0.001). The administration of hydroalcoholic oak extract (100 mg/kg) shortened the immobility time compared to the control group (P<0.05). The results of this study show that depression has no effect on locomotor activity. The hydroalcoholic extract of Quercus brantii (100mg/kg) significantly improved depression, decreased MDA and increased SOD. On the other hand, Quercus brantii oil (45%) has no significant effect on depression, but lowers MDA and increases catalase. 
Conclusion: Q. brantii appears to be a natural source of antidepressant compounds that increase antioxidant levels, which is currently being investigated by our group.