There are multiple studies of cranberry (juice or capsules) for the prevention of urinary tract infections in healthy women and nursing home residents. While no single study convincingly demonstrates the ability of cranberry to prevent UTIs, the sum total of favorable evidence combined with laboratory research tends to support this use. It is not clear what dose is best.Cranberry seems to work by preventing bacteria from sticking to cells that line the bladder. Contrary to prior belief, urine acidification does not appear to play a role. Notably, many studies have been sponsored by the cranberry product manufacturer Ocean Spray®. Additional research is needed in this area before a strong recommendation can be made.

Study results of cranberry as an antibacterial in other conditions show conflicting results. Further study is needed before a conclusion can be drawn.

Limited laboratory research has examined the antifungal activity of cranberry. There are no reliable human studies supporting the use of cranberry in this area.

Based on laboratory study, cranberry may have antioxidant properties. However, human study is lacking. Further study is needed before a recommendation can be made.

Limited laboratory research has examined the antiviral activity of cranberry. There are no reliable human studies supporting the use of cranberry in this area.

Preliminary research suggests that cranberry juice may increase vitamin B12 absorption in patients taking drugs that reduce stomach acid, such as proton pump inhibitors like lansoprazole (Prevacid®). However, this effect may be due to the acidity of the juice rather than an active component of cranberry itself. Further study is needed before a recommendation can be made.

Based on a small amount of laboratory research, cranberry has been proposed for cancer prevention. Study is needed in humans before a recommendation can be made.

Because of its activity against some bacteria, cranberry juice has been proposed as helpful for mouth care. However, many commercial cranberry juice products are high in sugar, and may not be suitable for this purpose. There is not enough research in this area to make a clear recommendation.

Based on preliminary research, it is not clear if drinking cranberry juice increases or decreases the risk of kidney stone formation. Cranberry juice is reported to decrease urine levels of calcium, increase levels of urine magnesium and potassium, and increase urine levels of oxalate.

Preliminary study results show that cranberry juice may increase overall ability to remember. Further well-designed clinical trials are needed to confirm these results.

Based on early research, cranberry may reduce the ability of H. pylori to live in the stomach. Further research is needed to confirm these results.

There is preliminary evidence that cranberry juice may reduce urine odor from incontinence or bladder catheterization. Further study is needed before a recommendation can be made.

In large quantities, cranberry juice may lower urine pH, making it more acidic. Contrary to prior opinion, urine acidification does not appear to be the way that cranberry prevents urinary tract infections.

There are no well-designed human studies of cranberry for the treatment of urinary tract infections. Laboratory research suggests that cranberry may not be an effective treatment when used alone, although it may be helpful as an adjunct to other therapies such as antibiotics.

It is proposed that skin irritation at urostomy sites may be related to urine pH. Cranberry juice can lower urine pH, and has been tested for this purpose. Further study is needed before a recommendation can be made.

There is preliminary evidence that cranberry is not effective in preventing urinary tract infections in children with neurogenic bladder.

There is preliminary evidence that cranberry is not effective in preventing urinary symptoms related to pelvic radiation therapy in patients with prostate cancer.