Kidney stones of 5-4mm in size are small stones in the kidney and do not require medication, extracorporeal shock wave lithotripsy or surgery. Most of the stones of this size can be excreted within 4 weeks with urine, but there are a few stones located in the lower calyces of the kidney, which cannot be excreted easily for a long time. They can also increase in size if they are not fed properly or if they are concentrated in urine for a long time. When the kidney stone is within this size range, it will not cause obvious symptoms of back pain and abdominal pain, nor will it cause patients to have symptoms such as frequent urination, urinary urgency or flesh-eye hematuria. Patients are advised to drink more water and urinate more every day, and to check regularly to see if the stones are discharged. If the size of the stone gradually increases more than 8mm during the review, extracorporeal shock wave lithotripsy is recommended to break the stone as soon as possible to facilitate the discharge of the stone from the body.