Cannabidiol CBD is the main component of cannabis extract which is a non - psychoactive substance with non - addictive low toxicity and high safety. CBD has shown unique advantages in tumor therapy and is being used on refractory epilepsy. Its mechanisms include as follows. ① Inducing cell cycle arrest and inhibiting tumor cell proliferation. ② Promoting tumor cell apoptosis through increasing ROS levels in tumor cells inducing mitochondrial dysfunction regulates Bcl-2 family proteins and inhibiting IAP family protein function. ③ Inhibiting tumor cell migration and invasion. ④ In conjunction with other anti - cancer therapies to exert a stronger anti-tumor effect. ⑤Relieve tumor-related symptoms such as pain anxiety and depression. ⑥It may play a role in regulating the tumor microenvironment. CBD has shown good anti - tumor properties in various tumor treatments and is expected to be used as a new tumor treatment drug in clinical practic. At present clinical trials related to CBD and cancer treatment mainly focus on analgesic treatment for patients with advanced tumors and its direct therapeutic effect still needs further clinical trials.