Triple negative breast cancer (TNBC) is an aggressive breast cancer with a high incidence of recurrence and poor prognosis even with the full spectrum of standard oncology treatments. Ever since its introduction about 100 years ago for cancer therapy, mistletoe viscum album extract (VAE) has been widely used in Europe as a popular complementary therapy for many cancers. We present a case of a patient diagnosed with stage 3c (T3N3bM0(i+)) TNBC who declined chemotherapy after a recurrence 2 years later. The patient received subcutaneous, intratumoral as well as intravenous VAE therapy for her recurrence. Her breast masses and lymph node sizes dramatically decreased under ultrasound examination within 2 months. After nearly three years since the tumor resolution, she is currently being managed on weekly subcutaneous VAE as well as intravenous VAE once in 6-8 weeks. She has excellent quality of life, no sign of tumor recurrence or other adverse side effects from her treatments. Though we believe the best outcomes in oncology are by integrating complementary and conventional care together, this case shows that VAE can have standalone effectiveness at least in some cases. Use of VAE to augment conventional treatments should be considered to bolster breast cancer care.