The present Single blind clinical trial will be conducted to determine the effects of bladder irrigation with normal saline on cystitis of catheterized patients in an Intensive Care Unit. 60 eligible patients will be randomly allocated to the experiment group (n=30) or control group (n=30). The inclusion criteria are: having urinary catheter, over 18 years old, suspected or asymptomatic bacteriuria induced by a urinary catheter. The exclusion criteria are: urinary catheter removal, patient's transfer or death, having chronic disease(Immunodeficiency, Diabetes mellitus, recurrent urinary tract infection before admission, anatomic problems and trauma to the to the genitourinary system, Chronic kidney disease, Acute or chronic glomerulonephritis, Pyelonephritis,
the use of Aminoglycosides، laboratory observer willnot know about patients' groups. Both groups will receive the routine care and medications. But, the experiment patients will receive bladder irrigation with normal saline once a day for 3 days with 500 ml. in three doses of 150 ml.The primary outcomes:ESR, leukocytosis, nitrite, number and type of bacteria.