Objective: To investigate various therapeutic effects of medicinal plant Ziziphus jujube (Z. jujube), such as antibacterial, antiviral, anticancer, anti-inflammatory and antioxidant properties. Methods: The present study was conducted to assess the beneficial effects of aqueous extract of Z. jujube fruit on the proliferation of breast cancer cells by MTT assay and the antioxidant by FRAP, haematological and biochemical alterations caused by NMU-induced mammary carcinogenesis in rats. The rats were divided into five groups, control group A (n=10), Z. jujube control group B (n=10), NMU control group C (n=15), Z. jujube treatment group D (n=15) and Z. jujube prevention group E (n=15). At the end of the experimental period, all the animals were euthanized and blood was collected by heart puncture. Results:The Z. jujube revealed a dose- and time-dependent cytotoxic effect against an MDA-MB-468 cell line and its treatment significantly (P<0.05) increased the total antioxidant capacity when compared to the NMU control group C. Z. jujube exhibited a preventive effect against anaemia, lymphocytosis and neutrophilia in group D and group E, when compared to group C. Biochemical analyses showed normal levels of enzymes of the liver in the Z. jujube treated groups: B, D and E rats, whereas NMU control group C showed significant (P<0.05) decreases in ALT, AST, albumin and total protein levels, and significant (P<0.05) increases in ALP and LDH. Conclusions: These findings indicate that the Z. jujube ameliorates the adverse effects of NMU carcinogenesis and could be useful for treating mammary tumours in humans.