The best treatment plan for kidney stones smaller than 0.4cm is to drink more water, urinate more often and observe the discharge of stones. kidney stones around 0.4cm are small stones in the kidney and can also be considered as meaningless stones that can be discharged into the bladder and out of the body through the ureter, unless adhesions occur in the body and can stay for a long time without being discharged. When doing surgery for urinary stones, if the stones are broken by laser to less than 0.4cm, it can be considered as a cured state and only need to discharge the stones by itself after surgery, neither any oral lithotripsy medicine nor extracorporeal shock wave lithotripsy is needed, let alone surgical treatment. Most stones under 0.4 cm can be excreted by urination within two weeks. A very small number of stones may stick to the kidney papillae or the mucosal wall of the renal pelvis for a long time, but they do not cause any harm and patients can simply drink more water.