Since ancient times, plants have been the source of traditional medicines for the treatment of various diseases throughout the world. Even today, the majority of purified drugs used clinically derived directly or indirectly from plants and other natural sources. Traditional Chinese medicine (TCM), the oldest form of medicine that has originated in ancient China, is rooted in the ancient philosophy of Taoism and dates back to more than 2500 years. As a holistic medicine, TCM has its theory and methods. TCM practitioners use a combination of different herbal medicines and various mind and body practices, such as acupuncture and tai chi, to treat or prevent health problems. Traditional Chinese medicine-based anticancer therapy is an old system but young in the field of modern medical science. In China, TCM herbals are widely used for cancer therapy and have gained increasing recognition worldwide in the recent years. The TCM-based herbal plants are being pursued by pharmaceutical companies as natural and rich sources for drug discovery. TCM has been recognized as a new source of anticancer drugs and new chemotherapy adjuvant to enhance the efficacy of chemotherapy and to ameliorate the side effects of cancer chemotherapies. Though TCM has been used since ancient times for preventing and healing disease, the scientific evidence at a molecular level behind the TCM is still mostly unknown, is rarely discussed, and needs to be known widely. Thus, this chapter reviews TCM oncology theory and its approach toward cancer, therapeutic effects, and various anticancer compounds obtained from TCM herbal plants with the hope of providing a better understanding on the role of drugs in the treatment of cancer.