Dr. Carolyn Dean, a naturopathic physician in Maui, Hawaii says there is still a role for cranberry juice and/or extract in preventing UTIs:

"We have been using cranberry juice extract and capsules for a long time. It stops adhesion of bacteria to the bladder wall. Sexually active women whose bladder feels irritated after sex should take cranberry capsules after intercourse as a preventative. If you do develop a UTI, you can increase the amount of cranberry extract you are taking or consider antibiotics."

Exactly how cranberries may prevent or treat UTIs is not fully understood, but cranberries contain fructose (fruit sugar) and type A proanthocyanidins, which can prevent E. coli from sticking to the said bladder walls. Antibiotics kill bacteria, while the cranberry extract provides more of a mechanical solution.

In the research, after one month antibiotic resistance to E. coli was higher than 85% in the antibiotic group and less than 30% among women who took the cranberry extract.

Antibiotics taken by mouth are usually recommended because there is a risk that the infection can spread to the kidneys.

For a simple bladder infection, you will take antibiotics for 3 days (women) or 7 - 14 days (men). For a bladder infection with complications such as pregnancy or diabetes, or a mild kidney infection, you will usually take antibiotics for approximately two weeks.

It is important that you finish all the antibiotics, even if you feel better. If you do not finish all your antibiotics, the infection could return and may be harder to treat.