Patients often ask in outpatient clinic: Recently, they often feel weak and achy, dizziness and tinnitus, often insomnia, is it a kidney deficiency? Can we know the severity of kidney deficiency by checking the kidney function? To deal with this question, we first need to have a general understanding of the “kidney” in Chinese medicine. The “kidney” in Chinese medicine and the “kidney” in western medicine are two completely different concepts. Chinese medicine believes that “the kidney is the foundation of the innate nature”. The main physiological function is to “hide the essence, the gas, the main water”, for the body of the fundamental yin and yang. Chinese medicine of the “kidney” contains the scope of far greater than the modern medicine referred to the kidneys, it is the dominant body of all vital activities of the power source, determines the growth and development of a person’s life, fertility, heredity, water metabolism, as well as the regulation of respiratory function, hair growth and moisturizing, and so on. Kidney” in Chinese medicine includes many systems of modern medicine, such as urinary, reproductive, endocrine, nervous and immune systems. Kidney qi is sufficient, the person’s breathing is deep and long, the hair is black and shiny, the sexual function is normal, the mental state is good, the body resistance is strong, the ability to reproduce offspring is strong. In Western medicine, the kidney is an organ of the human body, commonly known as the “waist”. Its main function is to filter the garbage in the blood, separate the metabolic waste and water, and excrete them through the bladder to maintain the acid-base balance of body fluids and health. Therefore, checking the kidney function cannot determine whether it belongs to kidney deficiency or not, and the high or low value of kidney function has nothing to do with the type and degree of kidney deficiency. Chinese medicine believes that the waist is the capital of the kidney, lumbago, especially after sex for a long time lumbago can not be restored, most of them belong to the kidney deficiency, is the main basis for judging the kidney deficiency: 1, the kidney division of the two stools: the kidneys and the bladder with each other, kidney qi is weak, it is easy to lead to urinary frequency, nocturia, the patient is generally no obvious pain in urination, urine routine examination of the normal, the mid-range urine culture without bacterial growth. Children show nocturnal enuresis. If the patient in the morning before dawn, that is, intestinal sound diarrhea, commonly known as “five more diarrhea” “kidney leakage”. It is mainly due to the deficiency of kidney yang, can not warm up the spleen and stomach. 2, kidney opening in the ear: kidney deficiency patients manifested as tinnitus, early light and heavy, gradually aggravated at a later stage, especially obvious at night, as if the robin kept chirping, affecting sleep. 3, the kidney is the main bone: tooth is the remainder of the bone, kidney essence is insufficient, tooth loss of nourishment, kidney qi deficiency, so the teeth withered, yellow and black, loose, easy to have caries. Where children’s teeth growth retardation, adult teeth loose or early loss, are caused by the lack of kidney essence. 4, the kidneys are the origin of the innate, the source of essence and blood: its China in the hair, the kidneys store essence, the liver stores blood, essence and blood each other, blood, blood is hair glory, blood failure is hair, if the liver and kidney deficiency, insufficient essence and blood, will lead to the hair is not glossy, easy to wither and fall off. The human body kidney essence is sufficient, the hair is normal development, manifested as thick, bright, soft. In short, kidney deficiency refers to the insufficiency of yin, yang, qi and blood of the kidneys, which is mostly manifested as a series of comprehensive symptoms such as lumbar and knee soreness and weakness, mental fatigue, tinnitus and deafness, hearing loss, insomnia and forgetfulness, hair loss, loosening of the teeth, osteoporosis, decline in sexual function, and weakness of the ulnar pulse. Clinically divided into kidney qi deficiency, kidney yang deficiency, kidney yin deficiency, kidney essence deficiency, etc.: 1, kidney qi deficiency: shortness of breath, sweating, tiredness and weakness, white color, frequent urination, spermatorrhea and premature ejaculation, pale tongue coating, pulse weak. Kidney yang deficiency: cold pain in the waist and knees, cold limbs, fear of cold, impotence, premature ejaculation, spermatorrhea, pediatric enuresis, pale fat tongue, thin pulse. Kidney yin deficiency: soreness and weakness of waist and knees, weakness of limbs, emaciation, hot flashes and night sweats, heat in the heart, dry throat and red cheekbones, dizziness and tinnitus, insomnia and dreaming, men’s yang is strong and easy to lift, women’s menstruation is scanty and menstruation is closed or there is a crash, yellow urine and dry stools, red tongue with little fluids and a fine pulse. 4, kidney essence deficiency: children’s delayed development, fontanel delayed closure, short stature, mental retardation, bone impotence, slow movement; men’s sperm less sterility, women’s menstrual period less menstrual closure, sexual frigidity; adult premature aging, hair loss, loose teeth, tinnitus, deafness, lumbar and knee soreness and weakness, dullness of the spirit, forgetfulness, tongue thin, pulse thin and feeble.