The present study aimed to evaluate the positive effects of amygdalin against mammalian tumors in-vivo. Twenty female albino mice, 4-6 weeks old age, were used, equally divided into four groups: group I (control) received no drugs; group II (carcinogenic group) received oral 7,12-dimethylbenz[a]anthracene (DMBA) (50 mg/kg once a weak) dissolved in sesame oil for 4 weeks; group III (therapeutic group) received oral Amygdalin (0.6 mg/kg/day) dissolved in 100% corn oil for 4 weeks after DMBA-induced tumor as in group II; group IV (protective group) received Amygdalin as in group III prior DMBA administration. The results showed that DMBA-induced mammalian tumors caused a significant increase in serum bilirubin (total & direct). Still, a substantial decrease in serum albumin as a hepatic function was recorded. Serum uric acid as a kidney marker revealed a significant increase. In addition, mammalian tissue L-malondialdehyde (L-MDA) concentration showed substantial growth and a considerable decrease in mammalian tissue total antioxidant capacity (TAC) concentration compared with the control group. However, the administration of Amygdalin was able to mitigate DMBA-induced mammalian tumors through decreasing total and direct bilirubin, uric acid concentration, as well as L-MDA concentration, along with a significant increase of TAC concentration in mammalian tissue. Additionally, hematological parameters of Amygdalin-administrated mice showed a substantial increase compared to mice with mammalian tumors induced by DMBA. Thus, it can be concluded that Amygdalin may successfully protect mammary tumors.