The mechanism of kidney stone formation is not fully elucidated, and some kidney stones have a clear etiology, such as sponge kidney, gout, urinary tract obstruction and infection. Some studies show that eating more greasy food, eating less dietary fiber or drinking too little water will promote stone formation. Stones less than 4mm can be discharged on their own, usually the body itself has no obvious feeling, you can observe the urine, to a month as an observation cycle. Stones larger than 4mm less than 6mm, by drinking more water, jumping way some of them can be discharged by themselves, some people will feel back pain or blood in the urine, this is the sharp part of the stone scraping the mucosa of the ureter or damage to the mucosa caused by. Stones larger than 6mm less than 1cm discharge process, some will have severe pain, which is too large stones discharged poorly.