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No evidence for ginseng

Ginseng root extracts have been used for many centuries, and the claims for it are that it can improve vitality, immune function, and help in cancer, cardiovascular disease and sexual problems. It is a big business, with over $100 million in sales in the USA a year, increasing at more than 25% a year. But does it work? A systematic review [1] concludes that the evidence is weak.


This included several databases, hand searching, contacting manufacturers and experts in herbal medicine. Studies were included if they were randomised double-blind studies of ginseng mono-preparations, and for any indication.


Sixteen studies met the inclusion criteria in a number of different indications.

Physical performance

There were seven trials, with 8-41 participants, all in healthy people, sportsmen or athletes with ages mostly under 40 years. Three of these found a statistical benefit for ginseng for some outcome, while four, the most recent, found none.

Psychomotor and cognitive function

There were five trials, with 19 to 127 participants. Four studies were in healthy volunteers, only one of which included people over 60 years. Three of these found a statistical benefit in favour of ginseng for at least one outcome like an arithmetic test. One study in elderly patients aged over 65 years found ginseng no better than control.


Two small studies examined the effects of ginseng on various immune-modulating factors in blood. One found changes, and one did not.


One small trial of 36 type-II diabetics found a significant improvement in glycosylated haemoglobin with ginseng.


One study found a significant improvement in frequency, severity and duration of herpes episodes compared with placebo.


Most of the trials included in this review look methodologically sound. The problem is that in any one indication the weight of evidence is slight. Moreover, most ginseng is taken for indications other than those tested in these studies. There is no evidence, for instance, that ginseng slows the ageing process or helps mental or physical functioning in the elderly. Some of the findings probably deserve another look.

A real strength of this quality review is that it examined not only the good things that ginseng may bring, but also the bad. Information on adverse effects is extracted from the trials and commented on authoritatively, together with other evidence from the literature. Ginseng is not universally benign, and may be associated with quite severe adverse effects and some drug interactions.


  1. BK Volger, MH Pittler, E Ernst. The efficacy of ginseng. A systematic review of randomised clinical trials. European Journal of Clinical Pharmacology 1999 55: 567-575.
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