Recently, I found that some patients and friends take medicine everywhere because they found kidney cysts, and some patients and friends worry about tumors and lose sleep, so I will popularize the scientific knowledge of kidney cysts to patients and friends: (1) Simple kidney cysts are the most common and least symptomatic kind of renal cystic disease, commonly found in adults over 50 years old and rare in children, so it may be acquired. It can be isolated or multiple, mostly seen in men and left kidney, often unilateral, but also combined with contralateral renal lesions. It is usually asymptomatic, does not affect renal function, and is occasionally seen due to the presence of hematuria. The vast majority of patients are found incidentally during B-mode ultrasound or CT examinations. Urinalysis is normal and hematuria is rare. However, renal cysts can cause abdominal pain and discovery of abdominal masses, hypertension, etc. If the cyst breaks into the pelvic calyx system, hematuria may be present. The cyst may also cause symptoms of obstruction of renal pelvis and calyces. (2) Simple renal cysts generally do not have many cysts in the kidney, the cystic cavity is not large, and the kidney function is normal, usually no treatment is needed, and regular review of B-type ultrasound is necessary. In case of pyelonephritis, the possibility of cyst infection should be thought of, and anti-inflammatory pain relievers can be used for pain in the kidney area. If the cyst is located at the renal hilum compressing the renal artery or causing obstruction in the renal calyces, and hypertension and large cysts (>5 cm in diameter) with symptoms are considered for puncture and removal of cystic fluid to eliminate hypertension and obstruction. After each puncture and aspiration, 2-5 ml of anhydrous alcohol should be injected respectively according to the size of the cyst in order to make the cyst gradually shrink. Generally, several puncture aspirations and injections of anhydrous alcohol are needed to close the bursa, and the patient’s blood pressure often decreases after aspiration of bursa fluid for decompression or cyst removal. If the treatment is not effective, surgical treatment will be taken if necessary. (3) Ultrasound is the preferred method of examination. Typical ultrasound shows no echogenicity in the lesion area, smooth cyst wall and clear border. When the cyst wall shows irregular echogenicity or limited echogenicity enhancement, it should be alerted to malignant lesions; when the cyst wall is thickened with secondary infection, there is fine echogenicity in the lesion area; when it is accompanied with bloody fluid, the echogenicity enhancement is enhanced; CT is valuable for those who cannot be determined by ultrasound examination. Cysts with bleeding or infection show heterogeneity and increased CT values. Diagnostic puncture may be unnecessary when CT shows cystic features. (4) Cyst puncture and cyst fluid examination When the diagnosis cannot be confirmed by ultrasound or CT or when malignant lesions are suspected, cyst puncture can be performed under the guidance of ultrasound and cyst fluid can be extracted for laboratory tests (5) This disease usually has no clinical symptoms and does not affect renal function, so the prognosis is good and does not affect the life expectancy of patients. Therefore, if it is simple kidney cyst, please do not take medicine everywhere. There is no point in taking medicine.