First, Cao Cao suffered from head wind disease because he personally led troops to fight for many years. Hua tuo's medical skill is superb, and he can relieve Cao Cao's pain as soon as possible. However, the good times did not last long. What can be done to solve it completely? Craniotomy? This is beyond Cao's understanding and acceptance. Huatuo was recommended to Cao Cao by his subordinate Hua Xin. Hua Tuo has a great talent in acupuncture. Hua tuo can easily relieve Cao Cao's head wind disease through simple acupuncture, but in the end acupuncture only treats the symptoms rather than the root cause, and can't completely solve the pain caused by the attack of head wind disease. So Hua Tuo suggested that Cao Cao be one? Craniotomy? It is easy to understand, but in Cao Cao's time, this hint would only make Cao Cao think that Hua Tuo was hurting him, so Cao Cao, who has always been sensitive and suspicious, decided to kill Hua Tuo.
Secondly, another reason why Cao Cao must kill Hua Tuo is that Hua Tuo deceived Cao, and Cao Cao was most concerned about his loyalty when he treated the head wind disease, and it took a long time for acupuncture to be effectively relieved. So, in order to cure the disease, Cao Cao decided to keep Hua Tuo with him as Cao Cao's physician. One day, however, Hua Tuo said that he had received a letter from home, and his wife was seriously ill and had to go back to her hometown. From then on, Hua Tuo changed forever. No matter how Cao Cao ordered him to come back, letters were like stones. Cao Cao was very angry about this. Cao Cao thought that Hua Tuo was not a loyal minister and wanted to improve his position by meeting Cao Cao. This was despised by Cao Cao, so Cao Cao sent someone to Huatuo.
The above is my answer, I hope it will help you.