Often, during outpatient consultations, patients often say to me: “My friend said that my current symptoms are just like his at that time, and that it is so-and-so disease”, “It was said on the Internet that this symptom of mine is so-and-so disease”; in response to online consultation patients also exist such questions as. “What exactly is my symptom?” ……………. The symptoms of a disease can be so varied that there is no ready-made formula or yes/no relationship to determine the diagnosis of a disease. If a symptom corresponded to a disease, then it would have been possible to create a computer program long ago and come up with a diagnosis of the disease by entering the symptom elements yourself at home; in fact there is no such software. The reason: 1. disease is a dynamic development process, just like a person’s appearance is completely different at different stages from birth to childhood, adulthood, middle age and old age; the impact of each period of disease development on the body’s function is also different, so naturally the same disease will have different symptoms; 2. different people will have different symptoms of the same disease, which is due to the genetic differences of each person leading to the susceptibility to disease and even the effectiveness of treatment. Like a cold, maybe you have a headache and runny nose, and you get better with oral Contec, but I have a cough, cough and fever, and Contec doesn’t work for me, but Heavy Sensation works very well for me; 3. Are they good or bad people? The human body is a three-dimensional body, under which there are skin, subcutaneous tissue, muscles, fascia, joints, internal organs, blood vessels, nerves and other tissues, except for the skin can accurately point out the location of the lesion other tissues are completely different types of sensory innervation, deep tissue lesions are not necessarily manifested in the painful It is as if we know that cholecystitis may have pain in the back of the shoulder, and appendicitis may have pain around the navel gradually shifting to pain in the right lower abdomen in the early stage, and the real lesion site can only be found through a comprehensive physical examination; therefore, the diagnosis of disease is totally unreliable by symptoms alone, and you can never judge whether the person is a bad person by looks alone. You have to corroborate your suspicions by all the evidence, and eventually all the evidence points to a criminal in order to convict. So how does a doctor make a diagnosis of a disease? First, the patient’s age, gender, and duration of illness are used to rule out diseases related to these factors. Second, translate it into a pathophysiological process based on the combination of symptoms, and list the tissues and organs from which the disease may originate. Third, to mentally deduce whether these diseases mentioned above would cause such symptoms, and again to exclude some of them. Fourth, do the corresponding physical examination after suspecting the possible diseases in mind to further exclude some diseases and narrow down the scope. Fifth, through the results of auxiliary examinations and imaging examinations to confirm whether the doctor’s diagnostic logic is accurate, if it does not match then repeat the second step to start screening again, and even sometimes still not sure, take the treatment of high suspicion of a disease (diagnostic treatment) to gradually exclude the disease from getting the diagnosis of the disease. The above 5 principles can be seen: since the manifestation of symptoms may be a reflection of many diseases, the doctor takes such a logical diagnostic method process is like: casting the net – reeling in the net – catching fish such a process, its efficiency is much higher than fishing; the advantage of this is respect for life and rigorous to avoid missing diagnosis, prevent and reduce the probability of mistakes in the process of growth of doctors, with the growth of experience the second, third and fourth steps to rule out the number of diseases will be more and more. The number of diseases excluded in the fourth step will increase and the speed of finalizing the diagnosis of the disease is accelerated. In addition, major life-threatening and crippling diseases can be ruled out first by prioritizing tests through such a principle. Such a step is a principle that must be followed by both famous doctors and small doctors, even if there are no advanced auxiliary examination means and imaging examination in ancient times, doctors also need to personally examine the patient to look, smell and cut, and never get an accurate diagnosis of the disease by consulting the network, the significance of the network to see the doctor is to help you determine the direction of consultation, less detours, that’s all.