Why do people get sick? This is really a particularly big topic, and I think it is also a question of particular concern to everyone, especially patients. Because I have been practicing medicine for more than twenty years, the most common question I have heard from millions of patients is why I am alive and why I have tuberculosis. Sometimes I find it very difficult to answer, but sometimes I feel that I must answer. After so many years of medical treatment, especially repeated on this issue, I think there are still some answers, these may not be comprehensive, some may not be correct, but I think as a family, as a longtime medical workers, it is necessary to write their own ideas, thinking for the readers to refer to, and out of the time also for discussion. The purpose is that people try to get sick less, or as few as possible fatal serious illnesses, as far as possible to maintain good health, both for their own sake, but also for their families, to put it in a larger sense is for the country or all of mankind. When it comes to sickness, the opposite is health, and on this topic, I think it is important to understand what health is in the first place. At this point, we humans now also have a long time ago, that is, in addition to the body’s various organs and tissues are functioning normally, there is no problem, and now also put special emphasis on mental health, that is, but also the spiritual aspects of the absence of problems, only the body, the spirit of the two aspects of the absence of problems, which is a truly healthy person. Writing this, we may understand what is unhealthy, that is, the state of disease, that is, in addition to the body of a certain organ, the organization out of the problem, the mental aspect of the problem, the same also for the state of disease. And with the progress of society, human beings continue to challenge themselves, it can be said that human beings are facing a variety of pressures increasing, so the chances of mental problems greatly increased. The following is to say a disease state, first of all, is the body of an organ, tissue and so on out of the problem, such as the respiratory system, digestive system, etc., then there will be a medical so-called symptoms, such as coughing, phlegm, abdominal pain, diarrhea, etc., such as the family has a doctor, or know how to doctor, generally first of all, their own diagnosis, their own treatment, such as the disappearance of the symptom or improve, also do not go to the hospital, such as the symptom persists or aggravate, it is inevitable to go to the hospital. It is inevitable to go to the hospital, and then is a variety of tests, through the examination to find the causative factors, and then the doctor to the symptoms of the drug, after a period of treatment, the symptoms improved or disappeared, stopping the drug, this is the end of a disease, but also a treatment of the termination of the clinic. Then the question comes, a family or a unit of comrades there are many, we all live in the same environment, work in the same office, work in the same factory, the work done is the same; such as a family, eat is the same, wear the same, such as couples also sleep in the same bed, why do I get sick, and he does not get sick, this is why?