General negative stones include uric acid stones or cystine stones, etc. Maximum 4mm can be used drugs include sodium bicarbonate of citrate and captopril. 1. If the stone surface is smooth and there is no urinary tract obstruction below the stone, uric acid stones can be treated by alkalizing the urine with sodium potassium hydrogen citrate and sodium bicarbonate, so as to discharge the stone. Or oral treatment such as allopurinol, studies have shown better results. 2. In the case of cystine stones, treatment requires alkalinization of the urine. Captopril can prevent the formation of cystine stones, and acetylcysteine also has a stone-dissolving effect. Regardless of the type of stone, medication should be accompanied by drinking large amounts of water to increase urine output, which also helps to expel the stone. The specific choice of medication should be made in a regular hospital, under the guidance of a doctor.