The post-operative complication of chylous leakage after breast cancer is relatively rare, and few clinical studies have been published. We report a 64-year-old woman with chylous leakage following modified radical mastectomy. We describe the patient’s diagnostic and treatment process in detail. The patient was diagnosed with grade II (left) breast invasive ductal carcinoma. Post-operatively, the patient's chest wall and axilla were pressurized, and negative pressure drainage was initiated. On the fifth post-operative day, the drainage from the chest wall and axilla increased significantly, and the patient developed chylous leakage on the eighth postoperative day. We injected meglumine diatrizoate (100 mL) and elemene (10 mL) into the patient's axilla, and the chylous leakage gradually resolved 18 days post-operatively. In this report, we focus on managing a case of chylous leakage after modified radical mastectomy for breast cancer. Meglumine diatrizoate combined with elemene is a possible treatment for the management of this rare complication.