Drowsiness, confusion and slowness in the advanced stage of liver cancer may be caused by tumor cells consuming the energy of the organism and physical weakness; it is also possible that the cancer cells have metastasized to the brain and infringed on the reticular arousal system, leading to consciousness disorder; liver cancer leads to the decrease of metabolic capacity of the liver, toxic substances enter into the brain and inhibit the electrical nerve activities of the brain, resulting in the emergence of hepatic encephalopathy, and so on. The details are as follows: 1. Weakness: Cancer cells can consume a lot of energy of the body, and patients with advanced stage of liver cancer have decreased their own digestion and absorption ability, which leads to insufficient nutrition and weakness of the body, unable to satisfy normal daily activities, and the patients have the performance of drowsiness, confusion and slowness. 2. Tumor metastasis: liver cancer cells can enter into brain tissue through blood and lymphatic channels. When cancer cells destroy reticular arousal system of cerebral cortex, the brain can’t maintain the body’s arousal state, and drowsiness, coma and other consciousness disorders will appear. 3. Hepatic encephalopathy: When liver cancer occurs, liver cells cannot metabolize excessive ammonia out of the body, resulting in elevated blood ammonia, which enters into the brain along with the blood, causing abnormal brain function. Symptoms such as drowsiness, confusion, slow reaction, delirium and coma will appear. When drowsiness, confusion and sluggishness occur in patients with advanced stage of liver cancer, it is recommended to go to the hospital as early as possible to improve the examination to remove the cause of the disease, and to treat the disease as early as possible to improve the prognosis and prolong the survival time.