This study is from Memorial Sloan-Kettering Hospital in New York, USA. Thousands of flexible cystoscopies are performed every day worldwide. Do they need antibiotic cover? Flexible cystoscopy may cause urinary tract infection (UTI) in less than 10% of cases. Asymptomatic bacteriuria may be common in some patients, but does not require antibiotics. Risk factors for UTI, such as smoking, increasing age, anatomical anomalies, diabetes, steroid use, immune deficiency and long-term catheter use, should be identified and patients should be treated judiciously. The major finding of this study is that significant UTI occurred in less than 2% of patients after cystoscopy and less than 5% in colonised cases, despite patients not receiving antibiotics. Overuse of antibiotics in such cases will lead to a potential worldwide rise in multi-drug resistant bacteria.