The current study was designated to investigate the effect ofAllium sativumon some physiological and immunological parameters in rats. thirty adult rats were divided into three groups (10 rat for each). G1: served as healthy control, G2 :rats were treated with 150 mg\kg of Allium sativum, G3: treated with 300 mg\kg of Allium sativum. All treated animals were givenorally for 30 days. The aspartate , ) ALT ( alanine transaminase on some parameters were investigated such as garlic effects of total and differential counts of white blood , ) LDH ( lactate dehydrogenase ), AST ( transaminase cells(WBC) like Lymphocyte, Monocyte, Neutrophil, Basophil, Eosinophil,as well as the level of and tumor ) GSH ( glutathione , ) CAT catalase ( , ) CRP reactive protein ( - C , ) MDA ( Malondialdehyde necrosis factor alpha (TNF-α) , the results administrated a significant decreased in the ALT and AST level in group treated with 150 and 300 mg\ kg of Allium sativum as compared with control also the results displayno significant in LDH level in treated groups with150 and 300 mg\kg of Allium sativum. The values of WBC show high significant increased in all groups treated with 150 and 300 mg\kg of Allium compared with control while the results obtained significant decreased in neutrophil in all groups that treated with 150 and 300 compared with control, also the results investigated a significant decreased in serum level of MDA, CRP,CAT, TNF-α while the level of CAT relieved significant increased in group treated with 150 and 300of aqueous extract of Allium sativum.