This description in the novel is only an exaggerated description to show Guan Yu's heroism. There should be no scientific basis for this poison control method. Generally, there are two kinds of poisons that can cause harm to human body, namely, paralyzing the central nervous system and destroying protein. In the former case, the poison will directly invade the central nervous system and paralyze it, and then die of respiratory failure or brain stop working. In the latter case, hemoglobin will be greatly destroyed, so that the poisoned person will gradually spread from the poisoned part to the whole body, and finally the respiratory system will be paralyzed and suffocated.