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Cranberries for preventing urinary tract infections

  • Review
  • Intervention




Cranberries have been used widely for several decades for the prevention and treatment of urinary tract infections (UTIs).


To assess the effectiveness of cranberry products in preventing UTIs in susceptible populations.

Search methods

We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library) and the Internet. We contacted companies involved with the promotion and distribution of cranberry preparations and checked reference lists of review articles and relevant studies.

Selection criteria

All randomised controlled trials (RCTs) or quasi-RCTs of cranberry products for the prevention of UTIs in all populations.

Data collection and analysis

Two authors independently assessed and extracted information. Information was collected on methods, participants, interventions and outcomes (UTIs - symptomatic and asymptomatic, side effects, adherence to therapy). Risk ratio (RR) were calculated where appropriate, otherwise a narrative synthesis was undertaken. Quality was assessed using the Cochrane criteria.

Main results

Ten studies (n = 1049, five cross-over, five parallel group) were included. Cranberry/cranberry-lingonberry juice versus placebo, juice or water was evaluated in seven studies, and cranberries tablets versus placebo in four studies (one study evaluated both juice and tablets). Cranberry products significantly reduced the incidence of UTIs at 12 months (RR 0.65, 95% CI 0.46 to 0.90) compared with placebo/control. Cranberry products were more effective reducing the incidence of UTIs in women with recurrent UTIs, than elderly men and women or people requiring catheterisation. Six studies were not included in the meta-analyses due to methodological issues or lack of available data. However, only one reported a significant result for the outcome of symptomatic UTIs. Side effects were common in all studies, and dropouts/withdrawals in several of the studies were high.

Authors' conclusions

There is some evidence that cranberry juice may decrease the number of symptomatic UTIs over a 12 month period, particularly for women with recurrent UTIs. It's effectiveness for other groups is less certain. The large number of dropouts/withdrawals indicates that cranberry juice may not be acceptable over long periods of time. It is not clear what is the optimum dosage or method of administration (e.g. juice, tablets or capsules). Further properly designed studies with relevant outcomes are needed.




在過去數十年, 蔓越莓經常被用來預防及治療泌尿道感染。




我們調查MEDLINE, EMBASE,Cochrane Control Register of Controlled Trials&網路資料。我也搜尋相關文章的參考文獻及拜訪推銷蔓越莓的公司。最近搜尋日期:2007年1月。




二位作者獨立地評估及選錄資料,所有有關方法、參與者、治療與預後 (泌尿道感染一有症狀無症狀、副作用、治療的連貫性) 的資訊都被收集。所得到的資料以相對風險 (RR) 呈現或是敘述性合成方法規 (narrative synthesis) 表現,以Cochrane的標準來分析其品質。


共選入10個研究 (1049個病患,5個交叉性,5個平行性) ,有7個研究分析蔓越莓果汁比對照組、果汁或水;有4個研究比較蔓越莓錠劑及對照組 (其中有一研究分析蔓越莓果汁與錠劑) 。與對照組比較下,蔓越莓產品在12個月間內可有效地降低泌尿道的發生率 (相對風險為0.65,95% 信賴區間0.46 – 0.9) 。蔓越莓產品對於婦女有復發性泌尿道感染比老年男性或女性或需要導尿管的族群,更能有效地降低泌尿道感染發生率。有6個研究因缺乏資料或實驗方法的問題而沒有選入,然而,只有一研究顯示蔓越莓對於有症狀的泌尿道感染之預後有正面的影響。所有研究顯示蔓越莓的副作用是很常見的,在有些研究中,病患中斷治療的比率很高。


有些證據顯示,針對有復發性泌尿道感染的婦女,蔓越莓汁在12個月內可降低有症狀泌尿道感染人數。對於其它族群,其效果並不確定。由於有很多的病患中斷治療,顯示許多病患無法接受長期使用蔓越莓汁,最佳的使用劑量或使用方法 (果汁、錠劑、膠囊) 目前仍不確定,仍須更多的研究來證實。



此翻譯計畫由臺灣國家衛生研究院 (National Health Research Institutes, Taiwan) 統籌。


蔓越莓 (通常是果汁) ,使用於試著預防泌尿道感染。蔓越莓有預防細菌附著在膀胱壁的物質。這總結共選入10個研究 (1049個病患) ,比較蔓越莓製品及對照組 (果汁水) ,有一些證據蔓越莓製品 (果汁與錠劑) ,可以預防婦女復發性泌尿道感染。但是這證據在老年男性和婦女之間不明確,在需要導尿管的族群是無效。很多人在這些研究分析中,停止使用蔓越莓果汁。喝多久會有效果,或需要多少劑量,結論並不明確。

Plain language summary

Cranberries for preventing urinary tract infections

Cranberries (usually as cranberry juice) have been used to try and prevent urinary tract infections (UTIs). Cranberries contain a substance that can prevent bacteria from sticking on the walls of the bladder. This may help prevent bladder and other urinary tract infections. This review identified 10 studies (1049 participants) comparing cranberry products with placebo, juice or water. There was some evidence to show that cranberries (juice and capsules) can prevent recurrent infections in women. However, the evidence for elderly men and women was less clear, and there is evidence that is not effective in people who need catheterisation. Many people in the trials stopped drinking the juice, suggesting it may not be a popular intervention. In addition it is not clear how long cranberry juice needs to be taken to be effective or what the required dose might be.