Assessment of red onion on antioxidant activity in rat

► This study investigated the effect of red onion on antioxidative activity in rat. ► The plasma SOD activity was significantly increased in the red onion peel and red onion groups. ► The GPx activity was significantly higher in the red onion flesh group. ► Liver catalase and ORAC activity showed upward tendency in the experimental groups. ► Liver malondialdehyde levels in the red onion group were significantly lower.