This is a single-center, double-blind, placebo-controlled parallel, pilot study of oral EW02 in combination with chemotherapy, versus placebo in combination with chemotherapy in breast cancer patients as the primary phase (Cycle 1). The chemotherapy regimen is restricted to one of the following regimens: Doxorubicin + Cyclophosphamide (AC), or Doxorubicin+ Cyclophosphamide+5-FU (CAF) under standardized dosage. The WBC recovery time is similar between these two chemotherapy regimens due to the facts that doxorubicin and cyclophosphamide are overlapped and their dose in CAF is reduced. The principle investigator has clinical experiences that the neutropenia nadir and severity caused by these two regimens are almost the same. Nevertheless, pre-stratification by chemotherapy regimen (stratum AC versus stratum CAF) at randomization will be implemented so that equal sample size of two study products will be allocated under each stratum. It will involve 60 outpatients for breast cancer, who have previously demonstrated a fall unto 1,000 to 3,000/mm3 in WBC count, or unto 500 to 1,500/mm3 in ANC count, on Day 8 or Day 15, whilst on Cycle 1.