It is now important to differentiate lower urinary tract infection also known as classical acute cystitis (because it involves a healthy genitourinary system) from complicated or potentially complicated urinary tract infection. The bacteriology of lower urinary tract infection is dominated by enterobacteria and Escherichia coli in particular. Since E. coli are now commonly resistant to amoxicillin and cotrimoxazole, those antibiotics cannot be used as first-intention. Fluoroquinolones, fosfomycin trometamol or furans must be preferred instead. The clinical problem here is trying to avoid overzealous diagnoses and remembering that symptom-free bacteriuria is very frequent, particularly in elderly patients. The management of uncomplicated lower urinary tract infection should remain simple (urinalysis with reagent strips and more cell bacteriology tests); the treatment should be simple too [single-dose or short treatment (3 days)]. The management of complicated lower urinary tract infection is very different however and requires a more extensive workup followed by a dual therapy, namely antibiotics and eradication of the complicating factor, if possible.