GINSENG is commonly used as herbal medicines with wide range of beneficial effects. It is also approved as effective agent against radiation hazards, through its immunomodulating role in irradiated experimental animals. This experiment aimed to assess cytogenetic and biochemical changes of ginseng at a working dose (100μg/ ml) in suppressing radiation effects of human peripheral blood. The treatment times were 6, 48 and 72h after γ-irradiation at dose of 4 Gy (the last two treatment periods were done through blood culture). Triple blood cultures for each blood sample were set up. Cytogenetic investigations were evaluated using chromosome aberration (CA) analysis and cytokinesis-block micronucleus assay (CBMN). The levels of malondialdhyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO) were estimated in blood plasma and in 48 & 72h blood cultures. In addition, immune function response was assessed by estimation of the levels of (Immunoglobulin G) IgG and IgM for the same treatment periods. Ionizing irradiation induced significant decrease of SOD activity. While, CA (dicentric, ring, breaks and polyploidy), micronucleus (MN), MDA level and NO concentration were significantly increased. For IgG and IgM, there is temporary over-production of them after 6h of irradiation, and then their levels decreased in the periods 48 & 72h within the cultures. Ginseng post-irradiation treatment exhibits increase in the level of IgG and IgM production, and improvement in NO concentration. In addition, there is reduction in the levels of lipid peroxidation (LPO), CA and MN frequencies. Results concluded that ginseng has antimutagenic effect and benefit against oxidative stress involved by irradiation.