Internal fire is also called internal heat, and Chinese medicine is also called "fiery endogenous". As the name implies, internal fire (heat) is the opposite of internal cold, which is caused by too fast metabolism and too much heat production. Excessive heat production, for the human body, there are two situations: absolute excess and relative excess. Absolute excess refers to diseases caused by excessive metabolism of human body, which leads to heat production exceeding normal heat dissipation capacity; And relatively too much refers to the disease caused by the relative excess heat production caused by the decline of human body's heat dissipation ability. Internal fire (heat) caused by excessive heat production is also called real fire (heat). Since it is a fire, its main clinical symptom is of course fever. The fever caused by "real fire (heat)" can be systemic or local. General fever is often manifested as an increase in body temperature. For example, hyperthyroidism in modern medicine belongs to the category of "internal fire (heat)" in traditional Chinese medicine. Local fever, such as burning sensation in stomach, heart socket, head and face, urethra during urination, anus during defecation, etc. It is caused by excessive accumulation of heat in a certain viscera. Clinically, excess fire (heat) often has symptoms of excessive metabolism besides fever, such as red face and red eyes, palpitation and upset, thirst, liking cold food, dry stool, Huang Chi urine, overeating, impatience and emaciation. There are many reasons for "excessive fire (heat)", the most important one is that Yuanyang's exercise and warming effect are too strong, which leads to excessive metabolic activities of human tissues and organs and produces various symptoms. In addition, all kinds of excessive emotional activities mentioned in emotional diseases are also a factor leading to "real fire (heat)", so I won't go into details here.

The heat dissipation system of human body is not only the heat dissipation of skin, sweat glands and breathing, but also the absorption and storage of heat by various liquid substances in the body, such as blood, body fluids and Yuan Yin, which is also an important factor to keep the body temperature constant and not too high. Therefore, when blood, body fluids, Yuan Yin and other substances in the human body are lost to a certain extent, there will also be an imbalance between heat production and heat dissipation in the human body, resulting in various fevers, which is the situation of relative excess heat production. Traditional Chinese medicine calls the internal fire (heat) caused by this relatively real heat "virtual fire (heat)". The main clinical symptom of "deficiency fire (heat)" is conscious fever, and the measured body temperature often does not rise or slightly rises (generally around 38℃, generally not exceeding 39℃). Fever is often more obvious in the afternoon or evening, and the symptoms will be aggravated after fatigue. In addition to fever, you can also see symptoms such as burning hands and feet, upset and insomnia, dry mouth and astringent eyes, dry throat and sore throat, hot flashes due to bone steaming, flushing on cheeks and so on. Blood, body fluids, Yuan Yin and other substances in the human body are the material basis for human physiological activities. People should consume these substances when completing physiological activities, and at the same time absorb nutrients from the diet, so that the consumed substances can be supplemented and filled. When people are overworked, exhausted after a long illness, bleeding too much, and eating improperly, it often leads to excessive consumption of liquid substances in the body and can not be replenished in time. At this time, "virtual fire (heat)" occurred. In addition, the liquid substances in the body will also be greatly reduced under the torment of "excess fire (heat)" and "fire (heat) evil" in the external six evils, thus causing the symptoms of "deficiency fire (heat)". This situation is more common in the late stage of fever infection. Patients with persistent low fever, mild or no fever in the morning, fever in the afternoon and at night, but generally not exceeding 39℃, listlessness, hunger and thirst but dislike drinking, anxiety and insomnia, dry throat, toothache, dry stool, short urine and so on. For this disease, it needs to be treated by nourishing yin liquid. Only by gradually replenishing blood, body fluid, Yuan Yin and other vaginal fluids lost in the body can the low fever gradually improve. In addition, improper treatment of fever, such as hyperhidrosis, will also damage the vaginal fluid in the body, leading to "virtual fire (heat)"

I once treated a little girl of 12 years old. After catching a cold and having a fever, her parents gave her antiperspirant and antibiotics themselves. She sweated a lot after taking the medicine. At that time, my temperature returned to normal, but I had a fever again the next afternoon. Her parents then gave her antiperspirants and antibiotics. After eating them, she broke out in a sweat, and the fever gradually subsided, but she came up again on the afternoon of the third day, which was higher than the next day. At this time, my parents began to feel uneasy and brought her to see me. It was morning when I came, and my temperature was 37.2℃. The little girl's mental state is ok, and her face is not red. She said that when the heating comes up in the afternoon, people will feel weak and don't want to move, and they have no appetite to eat these days. I asked her, how about defecation? She said that defecation is still normal. I asked her again, are you afraid of cold headaches? She said, no, but I feel phlegm in my throat and sometimes I cough a few times. At this time, my parents said that my body temperature was about 38.5℃ at home these two afternoons. I look at her tongue coating again, and it looks very dry, lacking body fluid, and the tip of her tongue is red. I feel my pulse is very soft and weak. According to various symptoms, I was diagnosed as "deficiency heat", and the cause was sweating, which led to the damage of body fluid. Prescription: 6 grams of Scrophularia, 6 grams of Polygonatum odoratum, 6 grams of asparagus, 3 grams of bamboo leaves, 3 grams of honeysuckle, 6 grams of Commelina communis, 6 grams of Cynanchum atratum, 6 grams of burnt hawthorn, 3 grams of raw licorice and 6 grams of burdock. In the prescription, Radix Scrophulariae, Polygonatum odoratum and Radix Asparagi are the main drugs, Bambusa Bambusae, Flos Lonicerae, Commelina communis and Cynanchum atratum are the auxiliary drugs, burnt hawthorn and raw licorice are used to stimulate appetite and digestion, Fructus Arctii is used to eliminate phlegm and relieve sore throat, and * * * is the auxiliary drug. * * * I ate three patches before and after, and my fever recovered.