The cranberry juice myth: it won't cure your UTI

Most urinary tract infections start when E. coli bacteria from the bowel travel up the urethra into the bladder. Women get them far more often than men, largely because a shorter urethra gives bacteria a shorter trip to reach the bladder — not because of poor hygiene or bad luck.

Here's the part people get backwards: cranberry doesn't work the way folklore says. Its proanthocyanidins may make it harder for bacteria to stick to the bladder wall, which is a prevention mechanism — it can modestly lower the odds of recurrent infections in some people. But cranberry juice does nothing to kill an infection you already have. A burning, painful UTI is a job for a clinician and, usually, antibiotics.

The most boring intervention may be the most powerful: hydration. In a randomized trial, women prone to repeat UTIs who drank an extra ~1.5 liters of water daily cut their recurrences roughly in half — more fluid means more flushing of bacteria before they can take hold. Other sensible habits include urinating after sex and not routinely 'holding it' for long stretches.

One more myth worth retiring: bacteria in the urine of someone with no symptoms (asymptomatic bacteriuria) usually should not be treated with antibiotics — doing so breeds resistance without helping. Symptoms, not test strips alone, drive treatment.