In the days when antibiotics were not available, infected stones were known as “malignant stone disease” because of the high mortality rate, recurrence rate and loss of kidney function. Although today’s minimally invasive techniques have made the treatment of urinary stones safer and more effective, lack of adequate knowledge of this particular stone can become a “trap” for extracorporeal and internal lithotripsy, leading to severe urogenital sepsis and even death due to infectious shock after surgery. The prerequisite for the formation of infected stones is a persistent urinary tract infection. About 1/3 of the pathogens causing urinary tract infections are due to urease producing microorganisms (fungi, bacteria, mycoplasma), but mainly bacteria, most commonly Aspergillus spp, Klebsiella spp, Pseudomonas spp and Staphylococcus spp. Although Escherichia coli is the most common causative agent of urinary tract infections, only about 1.4% of E. coli can produce urease, so it is not the main causative agent of infected stones. According to various trials and studies, infected stones grow rapidly and are characterized by rapid stone formation, with the fastest being 4-6 weeks to fill the entire urinary collection system and form antler-type stones that are confusing to treat clinically. Therefore, once a urinary tract infection occurs, it should be treated promptly to avoid recurrent attacks and development. Infected stones are mostly favored in women with urinary tract infections, diabetic patients, patients with neurogenic bladder and other patients who are weak and prone to recurrent urinary tract infections. Moreover, most infected stones occur in the kidney and rarely in the ureter. Those occurring in the bladder are mostly associated with urinary tract obstruction, neurogenic bladder and long-term indwelling urinary catheters in patients. Patients with infected stones mainly present with fever and bladder irritation caused by pyelonephritis, but many patients also have no symptoms. Another important manifestation of infected stones is back pain and hematuria caused by the stones, with the caveat that patients with infected stones rarely have renal colic. Urinalysis of patients with infected stones reveals pus and red blood cells in the urine, a urine pH greater than 7.0, and “coffin cap” crystals characteristic of magnesium ammonium phosphate. A urine bacterial culture with the presence of Urease bacteria is a strong indication of an infected stone. Once an infected stone is identified, it should be treated aggressively. Currently, the treatment of infected stones should be primarily surgical, with the goal of complete stone removal; it should be supplemented by pharmacological treatment for lithotripsy of residual stones after surgical treatment, or for patients for whom surgical treatment is not indicated. When the stone analysis determines that the stone is infected, active and effective pharmacological treatment should be taken immediately, mainly including: 1. Selecting specific drugs according to the urine culture and taking them for a long time to control the infection and make the urine sterile in order to achieve the purpose of eradicating the infection and prevent the infected stone component from being supersaturated; 2. Acidifying the urine: The dissolution of the infected stone component is highly dependent on the pH value of the urine. In vitro studies have shown that in an acidic state, the solubility of infected stones increases at pH values below 6.5. The target position of urine acidification for infected stones is pH 6.2, which is conducive to dissolving residual stones and preventing new stone formation, as well as strengthening the bactericidal effect of antibiotics; 3. Inhibit ammonia production, which aims to prevent stone recurrence and promote residual stone dissolution. Ammonia production after the decomposition of urea is the main reason for the formation of infectious stones. Inhibition of urease activity can stop stone growth or prevent the formation of new stones. How to avoid the recurrence of infected stones? Health promotion specifically includes: 1. Drink a lot of water, at least 2000ml per day to ensure the daily urine volume is above 2000ml; 2. Never quote alkaline drinks such as orange juice and cola to avoid alkalinization of urine and promote the growth of infected stones; 3. It is better to drink acidic drinks such as green plum fruit, apple juice and cranberry juice to facilitate acidification of urine; 4. Pay attention to personal hygiene to prevent urinary tract infection; 5. Avoid getting cold: especially avoid getting cold in the kidney area, bladder area and feet; 6. Regular physical examination: routine review of urinary routine and urological ultrasound every three months.