In this double blind prospective clinical trial, all patients with kidney stones and ureteral lithotripsy attended to the Babol Clinic 2014-2015 were enrolled. Inclusion criteria: minimum age 18 years, negative urine culture before ESWL; absence of Foley catheter or nephrostomy tube; no history of infectious stones. Exclusion criteria: patients who have not had suitable follow up; those who have done urine culture in the 2 weeks after ESWL; manipulation of the urinary system during and after ESWL. Patients are divided into two groups of A and B. Group A will be given 200 mg of Ofloxacin every 12 hours, preferably after surgery for up to 3 days and group B will be given placebo which is a pill made from flour. Then in all patients, 5 days before crusher surgery, urine culture will be done. Two weeks after ESWL, urine culture and ultrasound will be done and the information will be collected. Variables include size of the stones, the number and location of the stone, the Double j over the crusher. First variables will be given, including the amount of wave energy and crushed stone (immediately after ESWL) in the final stage of gathering information. Then we will check the following variables: the amount of crushed stone, the presence of renal colic after ESWL (response to oral pain medications and intravenous), the remaining stones larger than 5 mm ultrasound controls, urine culture results (presence of a colony of 105 ml / CFU to culture is seen as positive), urinary tract infection symptoms, frequency and urgency with positive culture, urinary sepsis.