Cancer toxicity is fundamental to tumorigenesis and transmission(metastasis) , and is present throughout the process of tumorigenesis and development. The combination of phlegm, dampness and stasis is the pathogenesis of cancer toxicity. The core pathogenesis of cancer toxicity involves "deficiency of positive Qi" and "phlegm and stasis intermingle to become poison". The core pathogenesis of the spread of cancer toxins is involved in the "deficiency of the ligaments and veins and loss of restraint", "cancer toxins intermingled with evil Qi" and "transmission of cancer toxins through the meridians". The principle of preventing and treating tumor metastasis is to support the positive Qi to resist cancerous toxins; it is necessary to pay attention to removing toxins by channeling the meridians, using a combination of herbal remedies, and to be guided by the idea of treating the disease before it arises by "first settling the place where the evil has not been received".