Prostate enlargement



 Enlargement of the prostate frequently causes older men unpleasant symptoms. These can include a weak urinary stream when emptying the bladder, inability to empty the bladder completely, straining, dribbling, needing to urinate often and and the feeling of not being able to hold the urine (urgency). This enlargement is called benign prostatic hyperplasia when the prostate growth is non-cancerous.

Men having this condition are frequently treated with pharmaceutical drugs to improve symptoms; all of which can have side effects. A variety of plant and herb extracts are often used as initial treatment to improve prostate symptoms. 

We present some of the evidence from Cochrane systematic reviews about complementary and alternative treatments related to prostate enlargement. This evidence comes from carefully researched reviews of information about clinical trials done to evaluate medical treatments. Studies are only included in these reviews if they meet pre-defined criteria.

It is very important to evaluate the available evidence about clinical effectiveness and beneficial and adverse effects of these alternative treatments. There are Cochrane reviews available for four possible therapies.

In the case of commercially available plant-derived products, it is important to be aware that different manufacturers or companies may use different extraction processes. It is not possible to be certain whether an extract from one manufacturer is equivalent of another's. And it is generally uncertain which of the many ingredients in a plant extract is the active one. Thus, it is possible that one product might have clinical efficacy while another apparently similar one does not.


Most men over 60 have urinary symptoms related to an enlarged prostate gland.  This condition is called benign prostatic hyperplasia. Using herbal and plant remedies to relieve its symptoms has become common.

The use of plant and herb extracts for treatment of benign prostate hyperplasia has been increasing over time. Pygeum africanum, an extract of an African prune tree, is one such preparation. It has become widely used in Europe for this purpose since its introduction in the late 1960s. Pygeum africanum is cheaper than many prescription medicines used for prostate hyperplasia.

Laboratory experiments suggest Pygeum africanum may have pharmacological properties that suggest it might possibly benefit men with prostate problems.

What the synthesised research says

Compared to placebo, Pygeum africanum provided a moderately large improvement in bothersome urinary symptoms and in urinary flow. Trials had some limitations and further study is desirable, but Pygeum africanum may be a useful BPH remedy.

The 18 randomised controlled trials analysed involved 1,562 men (see below) and lasted from 30 to 122 days. Men using Pygeum africanum were more than twice as likely to report an improvement in overall symptoms as men getting the non-active placebo. Their peak flow of urine increased by 23% and the amount of urine remaining in the bladder after voiding decreased by 24%. The need to urinate during the night decreased by 19%. 

Doses of Pygeum africanum used in the trials ranged between 75 to 200 mg per day. Most trials used a popular commercial extract called Tadenan but other extracts (such as Pigenil) were also used in a few of the studies.  Consistent with its greater European popularity, all the trials took place outside the United States.   

How it was tested

The researchers made a thorough search of the medical literature and also contacted manufacturers and researchers to identify controlled trials that assigned men randomly to Pygeum africanum or to placebo or another BPH treatment for at least a month.

Side effects and general cautions

Adverse effects of Pygeum africanum were mild and comparable to placebo. The most commonly reported side effect was gastrointestinal discomfort.

The trials identified mostly did not use standardised, validated assessments – such as the International Prostate Symptom Score or the Boyarsky score – for evaluation of urinary symptom improvement. Trials were relatively small in size and duration of trials was short, making long-term effects and benefits of taking Pygeum africanum for prostate hyperplasia uncertain. No trials were found that directly compared Pygeum africanum with known-to-be-effective remedies for prostate enlargement such as prescription alpha-blockers.


T Wilt, A Ishani, R Mac Donald, I Rutks, G Stark. Pygeum africanum for benign prostatic hyperplasia. The Cochrane Database of Systematic Reviews 1998, Issue 1. Art. No.: CD001044. DOI: 10.1002/14651858.CD001044.


About 30 plant-derived remedies are available and taken by men to improve benign prostate hyperplasia (BPH) urinary symptoms, with saw palmetto being the most widely used of these, especially in the United States. It is important to know whether these preparations are actually effective.

A large number of commercial preparations for prostate hyperplasia contain an extract from the fruit of the saw palmetto (also known as Serenoa repens or Sabal serrulatum), either by itself or in combination with other ingredients. The saw palmetto is a dwarf palm plant native to the Southern United States.

What the synthesised research says

Serenoa repens (saw palmetto) provides mild to moderate improvements in urinary symptoms and urinary flow. Men taking saw palmetto were almost twice as likely to report their urinary symptoms had improved as those men randomly assigned to taking a non-active placebo.

The degree of improvement was similar to that of finasteride (Proscar), with fewer side effects

Serenoa repens was comparable to finasteride (Proscar) and better than placebo in improving urine flow measures and residual amount of urine left in the bladder after urinating.

As with many prescription drugs for benign prostate hyperplasia, the long-term effectiveness and safety of

Serenoa repens and its ability to prevent prostate hyperplasia complications over time is not known.

How it was tested

The researchers made a thorough search of the medical literature as well as contacting manufacturers and researchers to identify controlled trials that assigned men with prostate hyperplasia randomly to either treatment with Serenoa repens or to a placebo or an alternate benign prostate hyperplasia treatment; and that lasted at least 30 days.

Twenty-one qualifying randomised trials involving 3,139 men were evaluated.  Trials lasted from 4 to 48 weeks. The most frequently-used dose of Serenoa repens was 160 mg twice a day. 

Side effects and general cautions

Adverse effects were generally mild. Around 1% of men experienced impotence (as compared with 5% of men taking finasteride (Proscar).  Around 1% of men taking Serenoa repens reported gastrointestinal symptoms. Nine per cent of men assigned to Serenoa repens discontinued taking the drug (as compared to 7% of men assigned to a placebo and 11% of men taking Proscar).

Unfortunately, there were no studies meeting pre-set inclusion crieteria that compared treatment with Serenoa repens with treatment with alpha-blockers (such as Minipress or Flomax), the most common class of medication used to treat BPH.

Trials often reported results in ways that were not strictly comparable from one trial to another, and dosages and preparations of Serenoa repens varied between trials. Some products used included other compounds along with Serenoa repens.

It is important to be aware that product purity or potency are not a given with plant preparations. A Consumer Reports investigation in 2000 found that independent analyses of saw palmetto preparations for sale revealed wide variation in the amount of Serenoa repens they contained. Tablet content often was different from product labelling. Different manufacturers often use different extraction processes and there is no knowing if one manufacturer’s product is equivalent to another’s.


T Wilt, A Ishani, R Mac Donald. Serenoa repens for benign prostatic hyperplasia. The Cochrane Database of Systematic Reviews 2002, Issue 3. Art. No.: CD001423. DOI: 10.1002/14651858.CD001423.


Numerous plant-derived remedies are available for treatment of bothersome urinary symptoms in older men caused by enlargement of the prostate (benign prostatic hyperplasia). Among these plant-derived remedies are some whose active ingredients are assumed to be cholesterol-like fats called beta-sitosterols.

Sterols are chemical compounds that are essential cell membrane components. In plants, sitosterols are the most abundant of these. Several plant-derived preparations used to treat prostate hyperplasia contain sterols from plant sources. For example, Harzol and Azuprostat contain an extract of South African star grass (Hypoxis rooperi). Other plant sterol preparations are derived from pine or spruce trees. The active components are thought to be beta-sitosterol and an associated component called beta-sitosterol-B-D-glucoside. 

What the synthesised research says

Four randomised controlled trials involving 519 men were analyzed. Beta-sitosterols generally improved urinary symptom scores, increased urine flow, and reduced residual urine volume after emptying the bladder. However, in one trial, urinary symptoms, urine flow and residual volume were not improved compared to placebo – that trial used a preparation containing only beta-sitosterol-B-D-glucoside rather than mixed sitosterols. Only one study looked at reduction in night-time urination, and in that study the beta-sitosterol product reduced the need to urinate by about one time a night. Taking beta-sitosterols did not reduce prostate size relative to placebo.

With the evidence suggesting that these preparations are well-tolerated and improve urinary symptom scores and flow measures, beta-sitosterols might be an option to try for men who want to avoid the side-effects of known-to-be-effective prescription alpha-blockers.

How it was tested

Researchers made a thorough search of the medical literature as well as contacting researchers to identify controlled trials that assigned men with benign prostate hyperplasia randomly to either treatment with a beta-sitoserol-containing plant extract or to a placebo or an alternate treatment, for a duration of at least 30 days.

Four studies met pre-determined standards and involved 519 men. Preparations used in the trials differed in their composition and the relative amounts and types of beta-sitosterols; and dosages also varied. Standardized doses and preparations of beta-sitosterols have not been clearly established.   

The long-term effectiveness and safety of these preparations and their ability to prevent benign prostate hyperplasia complications and progression over time is unknown.  

Side effects and general cautions

Side effects were generally mild with gastrointestinal effects reported in less than 2% of men and impotence even less often. The number of men withdrawing from the trials were comparable with beta-sitosterols and placebo. Trials were short in duration and do not provide evidence about long-term benefit or safety of beta-sitosterols. 

Trials were small in number and size, with overall fewer than 600 men participating, and had some methodological flaws. 


This record should be cited as: T Wilt, A Ishani, R Mac Donald, G Stark, C Mulrow, J Lau. Beta-sitosterols for benign prostatic hyperplasia. The Cochrane Database of Systematic Reviews 1999, Issue 3. Art. No.: CD001043. DOI: 10.1002/14651858.CD001043.


Enlargement of the prostate often causes bothersome urinary symptoms in older men. Plant-derived remedies are very popular worldwide for relief of benign prostate hyperplasia symptoms.

Cernilton is an extract of rye grass (Secale cereale) seed pollen. It is a popular remedy for benign prostatic hyperplasia and has been used by millions of men worldwide, especially in Europe. A single dose contains 60 mg of water soluble cerniton T60, and 3 mg of cernilton GBX, which (is an oil and) does not dissolve in water.

Cernilton shows some effect on cultured prostate cells in laboratory tests, but whether it actually does affect the prostate favorably and to a meaningful degree when taken in pill form is not certain. 

What the synthesised research says

Available evidence suggests that Cernilton may help relieve some urinary symptoms, but more research is needed. Although men in trials reported modest urinary symptom improvement, urine flow did not improve. 

How it was tested

The researchers made a thorough search of the medical literature and also contacted researchers and manufacturers to identify controlled trials that assigned men randomly to cernilton versus another benign prostate hyperplasia treatment or placebo, and lasted at least a month. Four trials were found involving 444 men. The trials lasted from 12 to 24 weeks. Two compared cernilton to placebo, one compared it to Tadenan (a Pygeum africanum extract), and one compared cernilton to Paraprost (a combination of amino acids available in Japan and used to treat prostate hyperplasia.

Side effects and general cautions

Trials were few and small, involving a total of fewer than 500 men. The methodological quality of the reported trials may also be questionable. Treatment durations were short, with no evidence available to evaluate long-term effectiveness or safety.

Adverse effects were rare with only one case of mild nausea reported. The number of men withdrawing from a trial who were taking cernilton was around 5% compared to less than 3% for placebo.

Although cernilton has been sold for years, the manufacturer, AB Cernelle/Graminex, recently discontinued cernilton in the United States, and is now using a changed manufacturing process and selling a rye grass seed pollen extract product which is not identical to that tested in the above trials (see - referenced August 5, 2006).


T Wilt, R Mac Donald, A Ishani, I Rutks, G Stark. Cernilton for benign prostatic hyperplasia. The Cochrane Database of Systematic Reviews 1998, Issue 3. Art. No.: CD001042. DOI: 10.1002/14651858.CD001042.