When one of my patients has a series of urinary tract infections, I recommend the same treatment, except the daily dose of cranberry capsule should be taken for three to four months. If the patient suffers no infections during that time, I take her off the product. Some patients will experience subsequent but infrequent infections that can be easily treated. However, others will suffer frequent recurrences. For them, I recommend maintaining the daily dose of a cranberry capsule, possibly for the rest of their lives.

If you enjoy the flavor of cranberry juice, one way to reap its benefits is to drink two to three glasses a day. Most cranberry juice or cocktails contain between 10 and 20 percent cranberry, and for some individuals such amounts are effective enough to prevent urinary tract infections. Although the benefits of drinking cranberry juice outweigh the negative effects of the sugar it contains, for people who are concerned about sugar, such as diabetics, sugar-free juice is available. If you don't find the cranberry flavor appealing or you require a higher cranberry concentration, many health-food stores carry concentrated cranberry capsules.

Why cranberry holds promise
Currently, the only alternative to cranberry for preventing urinary tract infections is to take an antibiotic regularly. This, however, is not always a good solution because of the risk of allergic reaction and of developing strains of bacteria resistant to antibiotics. On the other hand, the risk of allergic reaction to cranberry is negligible, and the bacteria have not been shown to be resistant to it. Thyme, goldenseal, and queen of the meadow are not effective as preventives, and some, such as goldenseal, should not be taken for long periods of time.

Cranberry also may be effective for patients who have difficulty emptying their bladder, such as men with enlarged prostates or patients with neurologic abnormalities including stroke or spina bifida. When urine remains in the bladder, bacteria have a greater chance of attaching to the bladder lining. Individuals with catheters also face an increased risk because bacteria can be introduced any time a foreign object enters the bladder. Although I know of no studies on this group of patients, it seems likely that cranberry may offer them badly needed relief.

D. Paul Barney is a family practice and emergency room doctor in Layton, Utah. He also is an adjunct professor at Weber State University and author of Clinical Applications of Herbal Medicine (Woodland Publishing, 1996).

Avorn, J.M., M. Monane, J.H. Gurwitz, R.J. Glynn, I. Choodnovskiy, and L.A. Lipsitz. "Reduction of bacteriuria and pyuria after ingestion of cranberry juice". Journal of American Medical Association 1994, 271:751 - 754.
Fowler, J.E. "Urinary Tract Infections in Women". Urologic Clinics of North America 1986, 13(4):673 - 683.