To assess the efficacy of ginseng root extract.

The authors searched the electronic databases of MEDLINE, EMBASE, BIOSIS, CISCOM, and the Cochrane Library from the database's inception to September 1998 using the search terms 'ginseng', 'panax' and 'eleutherococcus'. The authors also searched the bibliographies of retrieved studies and scanned personal files. Manufacturers of commercial ginseng products were contacted for further information and experts of herbal medicine were also contacted to provide published and unpublished material. There were no language restrictions.

Randomised controlled trials (RCTs) which were double-blind, placebo-controlled.

Mono preparations of ginseng root extract: Panax quinquefolium extract (618 mg or 1235 mg once daily), Panax ginseng (100 mg of a 4% or 7% ginsenoside concentration twice daily, 150 mg twice daily, or 200, 300, or 400 mg daily), Elagen (400 mg once daily) or Eleutherococcus senticosus (standard 625 mg daily or ESML 3.4 ml once daily) for the intervention groups. The control groups received vitamins, Ginkgo biloba, neurotrophic amino-acids, placebo, and/or exercise regimens.

Adult participants (healthy volunteers, patients with type-II diabetes, and patients of the Herpes Association) ranging in age from 18 to 80 years.

Exercise end points (physical and chemical measurements), psychomotor performance and cognitive function endpoints, leucocyte counts, mood, vigour and fasting blood glucose levels, and frequency, severity and duration of herpes episodes.

The authors do not state how the papers were selected for the review, or how many of the authors performed the selection.

The included studies were assessed for validity using Jadad's 5-point score (see Other Publications of Related Interest no.1). Two authors independently assessed the validity of the included studies. The authors met to agree consensus on the assessed data and discrepancies were resolved through discussions.

Two authors independently extracted the data using a standardised pre-defined form. The authors met to agree consensus on the assessed data and discrepancies were resolved through discussions.

Data were extracted for the categories of: study identification, Jadad score, study design, patient characteristics, specific interventions and controls (with dosages), primary study end points, main results and frequency of adverse effects.

The studies were combined in a narrative review.

Study differences discussed in the narrative review. Studies were grouped according to outcome measure.

Sixteen RCTs were included in the review with 643 participants (7 studies of physical performance with 182 participants; 5 studies of phschomotor performance and cognitive function with 252 participants; 2 studies of immunmodulation with 80 participants; 1 study of type-II diabetes with 36 participants; and 1 study of herpes with 93 participants).

Physical performance (n = 7): four trials found no improvement of physical performance after ingestion of ginseng. Other studies (3) found a decrease in heart rate and an increase in maximal oxygen uptake compared with placebo which persisted for 3 weeks after the treatment. All studies were in young active volunteers.

Psychomotor performance and cognitive function (n = 5: 4 in healthy volunteers (all placebo and controlled), and 1 in elderly people): 3 studies reported improvements (P < 0.05) in mental arithmetic and abstraction tests with Panax ginseng and in selective memory tests with Eleutherococcus. Four studies found that ginseng did not alter psychological functions or improve tolerability to exercise-induced stress.

Immunmodulation (n = 2; healthy volunteers): 1 study found an increase of the total number of T lymphocytes and of the activity of leucocytes compared with baseline (P < 0.05), but second, more recent study, found no effects.

Miscellaneous: study on patients with newly-diagnosed type II diabetes found that after 8 weeks psychological performance, mood and vigour were improved compared with baseline in both ginseng groups (P < 0.05), and there was a reduction of the fasting blood glucose level in both ginseng groups (P < 0.05). In a study on herpes patients there was a beneficial effect on frequency, severity and duration of herpes simplex type-II infections in the ginseng group compared with placebo (P = 0.0002).

The authors state that based on the results of this review, the efficacy of ginseng root extract is not established beyond reasonable doubt for any of the outcomes of the review.

The authors have clearly stated their research question and inclusion and exclusion criteria. The literature search was thorough. The quality of the included studies was formally assessed and results presented and discussed. The authors have reported on how the articles were selected and they have reported how many of the reviewers were involved in data extraction and how the data extraction was performed.

The data extraction is reported in tables and text and the narrative review was appropriate. The authors state that poor study quality, small sample sizes, varying doses and unclassified preparations of ginseng were limitations in the analysis of this treatment. The authors conclusions of no benefit from ginseng root extract appear to follow from the results.

Practice: The authors do not state any implications for practice.

Research: The authors state that the widespread use of ginseng as a herbal remedy warrants more rigorous investigations to assess its efficacy and safety.

1. Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJ, Gavaghan DJ, et al. Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials 1996;17:1-12.

This record is a structured abstract written by CRD reviewers. The original has met a set of quality criteria. Since September 1996 abstracts have been sent to authors for comment. Additional factual information is incorporated into the record. Noted as [A:....].