In our clinical treatment work, there are many diseases that patients already have obvious symptoms before they come to the hospital for examination. For example, patients who have recently lost weight, abdominal pain and diarrhea are found to have obvious anemia, and intestinal tumors are found to have grown in the intestines by colonoscopy. Patients with chronic headache found to have tumor in their brain. Patients who have been smoking for a long time until blood appears in their sputum are found to have lung cancer by CT. Patients with yellow eyes, sclera and urine had ultrasound to find tumors on the liver. Breast cancer is found only when a lump is felt in the breast and a small depression appears in the breast skin (orange peel sign). Occasional vaginal bleeding after menopause was thought to be normal, but a hysteroscopy was done to find out it was endometrial cancer. In addition to tumors, there are many chronic diseases, such as having significant dry mouth, excessive drinking and urination, blurred vision, and numbness in the hands and feet only to have a blood test to find significantly elevated blood sugar, and combined with kidney, retinal, and nerve damage. Chronic cholesterol elevation until the sudden pressure-like pain in the precordial region only to find that the heart was only the size of a fist had necrosis of a small piece. Chronic hypertension without medication fell headlong to the ground on one side of the body hemiplegic only to find out that the blood pressure was as high as 200mHg and intracranial hemorrhage. The patient accidentally slipped and fell at home and sat on the floor with back pain. 120 people were sent to the hospital for an X-ray bone scan before they discovered significant osteoporosis throughout the body. Such examples abound. The human body has a powerful compensatory system, for example, even after removing some organs (e.g., liver, kidney) or donating 400 ml of blood at one time in a blood donation van, there may be no obvious discomfort. Once clinical symptoms are manifested indicating that the balance of this system has been significantly disrupted, patients are often in the middle to late stages of the disease, with costly and ineffective treatment, plunging themselves into depression and placing a serious burden on their families. In fact, many diseases can be prevented, and one of the keys to prevention is regular medical checkups to detect diseases or the first signs of diseases when there are no obvious symptoms of discomfort.