The goal of this study was to compare the effects of kumquat extract and its chitosan nanoparticles on biochemical, histopathological, and parasitological factors in mice infected with Toxoplasma gondii versus spiramycin and control groups. A total of 35 mice, 7 of which were negative control and 28 was infected group, were used in the current study. All mice were sacrificed at 45 day after inoculation. Blood samples were collected. Then, sera Malondialdehyde (MDA), Catalase (CAT), Superoxide Dismutase 3 (SOD3), α-glutathione S-transferases (α-GST), and Interleukin 6 (IL-6) concentrations were measured using ELISA technique. In infected groups, CAT, SOD3, α-GST levels were decreased significantly (P<0.01), while MDA and IL-6 concentrations were significantly increased when compared to negative control (P<0.01). Treatment of infected mice with Kumquat-loaded chitosan nanoparticles were significantly improved (P<0.05) all parameters levels in sera and back them close to the original levels of negative control. The biochemical results are in parallel with histopathological and parasitological results. The findings imply that oxidative stress and parasitological changes may have a role in the aetiology and therapy of toxoplasmosis, particularly when Kumquat-loaded chitosan nanoparticles were used.