Cyclophosphamide is well known anticancer drug used for the treatment of several types of cancers. In combination with other drugs cyclophosphamide is prescribed to treat breast cancer, leukemia and ovarian cancer. But cyclophosphamide reduces the production of blood cells from the bone marrow. In the present investigation to combat the toxicity of cyclophosphamide, aqueous extract of immunomodulator plant like Ashwagandha was studied against toxicity of cyclophosphamide. After administration of cyclophosphamide @ 250 mg/kg b.w. (tablet) orally by gastric intubation method to rats, marked reduction in total count of WBC, ALC and Platelets were observed and slightly reduction in RBC was observed on day 4th. When Ashwagandha (300mg/kg b.w.) administered five days prior to cyclophosphamide administration and continued for ten days then significant increase in total count of WBC, ALC and Platelets were observed after treatment but there is no significant statistical difference in the RBC count was seen in all groups during the period of the study. Thus findings of present investigation showed that therapeutic potency of Ashwagandha ameliorate the toxicity produced during cancer chemotherapy by mitigating the bone marrow depression.