Preventing the change of the disease refers to the initial stage of the disease, we should strive to achieve early diagnosis and early treatment to prevent the development and transmission of the disease. Early diagnosis and treatment Early diagnosis and treatment, the disease is still in the early stage, the disease position is shallow, the condition is mostly light, the righteousness is not yet decayed, the disease is easier to treat, and therefore the transmission is less. The timing of early diagnosis and treatment is to grasp the occurrence and development of different diseases and their transmission rules, so that a correct diagnosis can be made in time at the beginning of the disease, thus providing timely, effective and thorough treatment. If not timely diagnosis and treatment, the disease may be deepened step by step, making the disease more and more complex and serious, and the treatment will be more and more difficult. Second, to prevent the transmission 1, intercept the disease transmission pathway. Diseases generally have their certain transmission rules and pathways. Such as typhoid transmission of the six meridians, the beginning of the disease in the muscular surface of the sun meridian, the development of the disease is easy to other meridian transmission, therefore, the sun stage is the key to the early diagnosis and treatment of typhoid, the correct and effective treatment at this stage, is the best measure to prevent the development of typhoid; also such as warm disease began with the Wei part of the evidence, therefore, the Wei part of the evidence stage is the key to the early diagnosis and treatment of warm disease. Accordingly, it can be seen that, after the invasion of the body, according to the law of transmission, early diagnosis and treatment, intercept the pathway of disease transmission, can prevent the deepening and deterioration of the disease. 2, the first security is not affected by the evil of the ground to the five elements of the law of birth, gram multiplied by insult, or meridians as a guide to protect the internal organs not affected by the evil in advance. If the internal organs have disease, there can be and son, offending mother, multiply, insult and other transmissions. Therefore, according to the law of transmission of different lesions, the implementation of anticipatory treatment can control their pathological transmission. For example, the “Jin Kui Yao – the pulse evidence of successive diseases of the internal organs and meridians” says: “When we see liver disease, we know that the liver transmits the spleen, so we should first strengthen the spleen.” Clinically, while treating liver disease, often with drugs to regulate the spleen and stomach, so that the spleen is strong and not subject to evil, can really receive good results. Another example is that when a warm-heat disease injures stomach yin, the development trend of the disease will consume kidney yin. According to this law of transmission, the Qing dynasty doctor Ye Tianshi put forward the prevention and treatment principle of “first to protect the place that has not been affected by evil”, advocating the addition of salty-cold nourishing kidney yin drugs to the prescription of sweet-cold to nourish stomach yin, in order to prevent the depletion of kidney yin. All these are effective applications of the principle of prevention and treatment of both diseases.