Cytotoxic chemotherapy has been a primary modality for both solid and hematologic cancers. Despite improving clinical outcomes, chemotherapy-induced toxicities, in particular, myelosuppression continues to be a major clinical challenge. Drug-induce myelosuppression can affect neutrophils, lymphocytes and platelets individually or a combination of these hematopoietic lineages. The reduction in these cells increases the risk for bacterial, fungal or viral infections that may require immediate and aggressive management. The advent of Neupogen and Epogen with their capability to ameliorate chemotherapy-induced neutropenia and anemia has transformed how chemotherapy-induced myelosuppression is managed. In a Phase I/IIa clinical trial, we have found an active peptide in the renin angiotensin system (RAS), angiotensin (1-7) (A(1-7)), reduced grade 2-4 anemia, thrombocytopenia, and lymphopenia as well as mucositis when compare to controlled patients receiving rhG-CSF alone. In a Phase IIb study, Mas receptor agonist A(1-7) reduced the incidence and severity of thrombocytopenia in subjects receiving a combination of gemcitabine and platinum for ovarian carcinoma and allowed maintenance of chemotherapy dose density.