The EC regimen for breast cancer is a commonly used intravenous chemotherapy regimen, with R being the abbreviation for epirubicin and C being the abbreviation for cyclophosphamide, which are the two most commonly used chemotherapy drugs for breast cancer treatment. The EC regimen is an adjuvant regimen used in the treatment of breast cancer patients with positive lymph nodes. The most common side effects of epirubicin are cardiotoxicity and hair loss, and the most common side effect of cyclophosphamide is liver and kidney damage. During chemotherapy, cardioprotective, hepatoprotective and renoprotective drugs should be routinely given, and patients should be advised to drink more water to speed up the metabolism of the drugs.