Now cranberries are just for Christmas – new evidence suggests cranberry juice unlikely to prevent urinary tract infections

Key message: The current evidence suggests that any benefit of taking cranberry products to prevent urinary tract infection is likely to be small and people may find taking them over a long period of time unacceptable.

As garlic is to vampires, so cranberries are to urinary tract infections (UTIs); or so many people believe, drinking cranberry juice in the hope of avoiding bouts of this unpleasant complaint. Cranberry products have been used for this purpose for a very long time and though it’s unclear how they might help, one theory is that cranberries prevent bacteria from sticking to the walls of the bladder.

Up to now, there has been some Cochrane evidence to support a role for cranberries in preventing UTIs. A review first published in 1998, which looked at the effectiveness of cranberry products in preventing UTIs in people who are susceptible to them, found some evidence to show that cranberry juice can reduce the number of infections in women who tend to get them repeatedly. In the latest update of this review published today in the Cochrane Library, evidence from 14 new studies suggests that cranberry juice is less effective than previously thought.

The review now includes 24 studies with a total of 4,473 people. Adult women were the most studied, but other subgroups at risk of UTIs, such as pregnant women, children and older adults were included. People who were given cranberry juice, capsules or tablets were compared with people given water, methenamine hippurate, antibiotics, lactobacillus, placebo products or nothing.

What did they find?

  • A small trend towards fewer UTIs in women taking cranberry products compared with those taking a placebo or nothing was shown in some small studies, but no significant differences when the results of a larger study were added
  • No significant benefit of cranberry products compared to placebo or no treatment for any other subgroups of people at risk of UTI
  • Cranberry products were not significantly different to antibiotics for preventing UTIs in three small studies
  • Many people stopped taking the cranberry products, especially the juice, and dropped out of the studies

How good is the evidence?

The review authors judged the studies to be generally robust but point out some problems, including:

  • a lack of information about the amount of active ingredient in cranberry capsules or tablets
  • not including in the final analysis a large number of people who were allocated to treatments at the start, which can introduce bias in the results
  • most studies were small and lacked power to detect significant differences between groups


Full citation:Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database of Systematic Reviews 2012, Issue 10. Art. No.: CD001321. DOI: 10.1002/14651858.CD001321.pub5.

Funding for the 2012 update of the review was provided by the National Institute for Health Research (NIHR) (

Cochrane Summary and podcast available:

Podcast by Ruth Jepson:

Wiley Science Newsroom has highlighted this review and you can read the press release here.

The Independent:

BBC News Scotland:

ABC News:

The Herald Scotland:

Science Daily:

News Medical:

Med Page Today:

Medical Xpress:

Now cranberries are just for Christmas – new evidence suggests cranberry juice unlikely to prevent urinary tract infections by Sarah Chapman

is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International

3 Comments on this post

  1. Pretty great post. I just stumbled upon your blog and wished to say that I’ve really enjoyed surfing around your weblog posts. In any case I will be subscribing to your feed and I am hoping you write again soon! begdckaddfed

    Johnc648 / Reply
    • Thank you. We’re exploring new ways to get the evidence ‘out there’ and we’re increasingly including ‘expert’ views, both patients and practitioners. Blogs are published weekly but we also have some special weeks with several blog: palliative care week is coming soon!

      Sarah Chapman / (in reply to Johnc648) Reply
  2. Surely an interesting and hugely relevant review. Cranberries in many forms are suggested by doctors as well and it is very helpful to have this review to sort out what we can and cannot attribute to these. This has generated wide interest and I have come across this in places ranging from the lay press to Medscape updates, so surely being noticed by many. Well done!

    Mohit Sharma / Reply

Leave a Reply

Your email address will not be published. Required fields are marked *