With the progress of society, the pace of life faster and faster, the mental pressure is getting bigger and bigger, all kinds of sub-health state is more and more, all day long dizziness, low mood, cervical spondylosis, insomnia, dreamy, sweaty, emotionally irritable, lumbar and knee soreness, tinnitus, obesity, hypertension, diabetes, hyperthyroidism … … in the long run, all kinds of chronic diseases, and even tumors make the human being who should be able to enjoy his life to wither away too soon! … Western medicine focuses on symptomatic supportive treatment, and has no advantage in disease prevention. Modern society divides doctors into three levels: junior, intermediate and senior. They are promoted mainly through scientific research. Our ancestors used to categorize doctors into three grades: upper medicine, Chinese medicine, and lower medicine. The “superior doctor treats the disease before it occurs, the Chinese doctor treats the desire disease, and the inferior doctor treats the disease that has already occurred”, i.e., the doctor with the highest level of medical skills is not the one who specializes in treating diseases, but the one who is able to prevent diseases. It can be seen that Chinese medicine has always emphasized prevention over cure. There are three causes of human death: one is no disease; second is an accident; third is due to disease and death. The first two accounted for 20%, while the latter accounted for 80%. It can be seen that disease is still the main cause of death. So, how can we not be sick? Here, it is clearly stated that the “spirit of internal guardianship”. The so-called “spirit of internal guardianship”, mainly refers to the person’s own conscious thinking activities and psychological state of self-exercise, self-control, self-regulation, so that it and the body, the environment to maintain a coordinated balance and the ability not to be disordered. The term “internal” is used to refer to the external; the term “keep” means “hold on to” and “keep”. The phrase “keep the spirit within, and the disease will be safe” emphasizes the importance of mental stability in maintaining health. One should not welcome things before they happen, one should not worry too much when things happen, and one should not keep things after they happen, but listen to them as they come. It should be natural, let it go, wrath and fear, good music and sorrow, all get its right, this is the method of nourishing the heart.