This study investigated the effect of daily oral administration with allicin levels (0, 5 and 10 mg/kg of female body weight), 30 days pre‐insemination, on reproductive performance in vivo and in vitro, immunity, and oxidative stress of rabbit does under high ambient temperature. Niliparous NZW does (n = 105) were randomly divided into three groups (35 in each) treated with 0, 5 and 10 mg allicin dissolved in 2 ml distilled water, respectively, for 30 days pre‐insemination. At the end of treatment (30 days), does were artificially inseminated with fresh diluted semen of 20 fertile NZW bucks. Reproductive performance and ovulatory response parameters were determined. Serum biochemicals, enzyme activity, immunoglobulins (IgG and IgM) and antioxidant status were determined on day 30 of treatment. Serum progesterone and prolactin were determined pre‐insemination (30 days of treatment), on 15 days of pregnancy and 7 days post‐partum. Results showed that both allicin levels increased live litter size, and bunny viability rat and litter size at birth and weaning. Allicin levels increased ovulation rate and improved embryo quality. Number of total follicles decreased only with 10 mg allicin. Progesterone increased pre‐insemination, 15 days of pregnancy and 7 days post‐partum progesterone by allicin levels. Prolactin pre‐insemination and on day 7 post‐partum increased with 10 mg allicin. Serum total proteins, albumin, globulin, IgG and IgM increased, while glucose, aspartate and alanine aminotransaminases, and thiobarbituric acid reaction decreased by both allicin levels. In conclusion, the mechanism by which allicin administration 30 days pre‐insemination to improve the reproductive performance of rabbit does is based on that allicin can play an important role, as a natural exogenous antioxidant, increasing immune response and reducing lipid peroxidation.