Misconception: Drinking buckets of cranberry juice can cure, and even prevent bladder, infections.

Actually: You may enjoy the taste (see: vodka) but it won’t cure and, probably, won’t prevent recurrence.

This purported remedy is centuries old and there is a considerable amount of research investigating it. While some studies suggest that cranberry may reduce repeated infections in younger women, it is certainly not a treatment for an active case. The gold standard for treatment is antibiotics. Sometimes doctors just recommend rest and ibuprofen.

“I was hoping it would work,” said Dr. Manisha Juthani-Mehta, an infectious disease specialist at the Yale School of Medicine, and the lead author of a study published Thursday in the journal JAMA, which showed no reduction in urinary tract infections for female nursing home patients who took standardized, high-dose cranberry capsules — the equivalent of 20 ounces of juice daily — for a year.

“I’m not sure it’s worth spending money on, particularly for patients on a fixed income, ” she said.