Recommendations for reporting randomized controlled trials of herbal interventions: explanation and elaboration

  • Joel J. Gagnier
    Corresponding author. 5955 Ontario Street, Unit #307, Windsor, Ontario, Canada, N8S1W6. Tel.: +1-519-974-9690; fax: +1-519-258-2396.
    Department of Health Policy, Management and Evaluation, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada

    Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada
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  • Heather Boon
    Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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  • Paula Rochon
    Department of Health Policy, Management and Evaluation, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada

    Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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  • David Moher
    Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada

    Department of Pediatrics, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada

    Department of Epidemiology & Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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  • Joanne Barnes
    Centre for Pharmacognosy & Phytotherapy, School of Pharmacy, University of London, London, United Kingdom
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  • Claire Bombardier
    Department of Health Policy, Management and Evaluation, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada

    Institute for Work & Health, Toronto, Ontario, Canada
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  • for the CONSORT Group
    Author Footnotes
    1 Members of this group are listed in Section 8.
  • Author Footnotes
    1 Members of this group are listed in Section 8.


      Controlled trials that use randomized allocation are the best tool to control for bias and confounding in trials testing clinical interventions. Investigators must be sure to include information that is required by the reader to judge the validity and implications of the findings in the reports of these trials. In part, complete reporting of trials will allow clinicians to modify their clinical practice to reflect current evidence toward the improvement of clinical outcomes. The consolidated standards of reporting trials (CONSORT) statement was developed to assist investigators, authors, reviewers, and editors on the necessary information to be included in reports of controlled clinical trials. The CONSORT statement is applicable to any intervention, including herbal medicinal products. Controlled trials of herbal interventions do not adequately report the information suggested in CONSORT. Recently, reporting recommendations were developed in which several CONSORT items were elaborated to become relevant and complete for randomized controlled trials of herbal medicines. We expect that these recommendations will lead to more complete and accurate reporting of herbal trials. We wrote this explanatory document to outline the rationale for each recommendation and to assist authors in using them by providing the CONSORT items and the associated elaboration, together with examples of good reporting and empirical evidence, where available, for each. These recommendations for the reporting of herbal medicinal products presented here are open to revision as more evidence accumulates and critical comments are collected.


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        • Altman D.G.
        • Schulz K.F.
        • Moher D.
        • Egger M.
        • Davidoff F.
        • Elbourne D.
        • et al.
        The revised consort statement for reporting randomized trials: explanation and elaboration.
        Ann Intern Med. 2001; 134: 663-694
        • Mulrow C.D.
        • Cook D.J.
        • Davidoff F.
        Systematic reviews: critical links in the great chain of evidence.
        in: Mulrow C. Cook D. Systematic reviews: synthesis of best evidence for health-care decisions. Philadelphia, PA, ACP1998
        • Sackett D.L.
        • Richardsom W.S.
        • Rosenberg W.
        • Haynes B.
        Evidence-based medicine: how to practice and teach EBM.
        Churchill Livingston, New York, NY1998
        • Schulz K.F.
        • Chalmers I.
        • Hayes R.J.
        • Altman D.G.
        Empirical evidence of bias: dimensions of methodological quality associated with estimates of treatment effects in controlled trials.
        JAMA. 1995; 273: 408-412
        • Moher D.
        • Jadad A.R.
        • Tugwell P.
        Assessing the quality of randomized controlled trials: current issues and future directions.
        Int J Technol Assess Health Care. 1996; 12: 195-208
        • Jadad A.R.
        • Moore A.
        • Carroll D.
        • Jenkinson C.
        • Reynold D.J.
        • Gavaghan D.J.
        • et al.
        Assessing the quality of reports of randomized clinical trials: Is blinding necessary?.
        Control Clin Trials. 1996; 17: 1-12
        • Begg C.B.
        • Cho M.K.
        • Eastwood S.
        • Horton R.
        • Moher D.
        • Olkin I.
        • et al.
        Improving the quality of reporting of randomized controlled trials: the CONSORT statement.
        JAMA. 1996; 76: 637-639
        • Moher D.
        • Schulz K.F.
        • Altman D.
        • for the CONSORT Group (Consolidated Standards of Reporting Trials)
        The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomized trials.
        JAMA. 2001; 285: 1987-1991
        • The CONSORT Group
        (Accessed Nov 1, 2004. Available at)
        • Ioannidis J.P.A.
        • Evans S.J.W.
        • Gøtzsche P.C.
        • O'Neill R.T.
        • Altman D.G.
        • Schulz K.
        • et al.
        • for the CONSORT Group
        Improving the reporting of harms in randomized trials: expansion of the CONSORT statement.
        Ann Int Med. 2004; 141: 781-788
        • MacPherson H.
        • White A.
        • Cummings M.
        • Jobst K.
        • Rose K.
        • Niemtzow R.
        Standards for Reporting Interventions in Controlled Trials of Acupuncture: The STRICTA Recommendations.
        Acupunct Med. 2001; 20: 22-25
        • Linde K.
        • Jonas W.B.
        • Melchart D.
        • Willich S.
        The methodological quality of randomized controlled trials of homeopathy, herbal medicines and acupuncture.
        Int J Epidemiol. 2001; 30: 526-531
        • Moher D.
        • Sampson M.
        • Campbell K.
        • Beckner W.
        • Lepage L.
        • Gaboury I.
        • et al.
        Assessing the quality of reports of randomized trials in pediatric and complementary and alternative medicine.
        BMC Pediatrics. 2002; 2
        • Linde K.
        • ter Riet G.
        • Hondras M.
        • Vickers A.
        • Saller R.
        • Melchart D.
        Systematic reviews of complementary therapies—an annotated bibliography. Part 2: Herbal medicine.
        BMC Complement Altern Med. 2001; 1: 5
      1. Gagnier, JJ, VanTulder, M, Bombardier, C, Burman, B. Botanical medicine for low back pain. Cochrane Review (Protocol Published 2003).

        • Little C.
        • Parsons T.
        Herbal therapy for treating rheumatoid arthritis.
        Cochrane Library. 2000; 4
        • Gagnier J.J.
        • DeMelo J.
        • Bombardier C.
        Quality of reports of randomized controlled intervention trials of herbal medicines.
        Am J Med. 2006; (in press)
        • Campbell M.K.
        • Elbourne D.R.
        • Altman D.G.
        • for the CONSORT Group
        CONSORT statement: extension to cluster randomized trials.
        BMJ. 2004; 328: 702-708
        • Gagnier J.J.
        • Boon H.
        • Rochon P.
        • Barnes J.
        • Moher D.
        • Bombardier C.B.
        • for the CONSORT Group
        Reporting randomized controlled trials of herbal interventions: an elaborated CONSORT statement.
        Ann Int Med. 2006; 144: 364-367
        • Mix J.A.
        • Crews W.D.
        A double-blind, placebo-controlled, randomized trial of Ginkgo biloba extract EGb 7611 in a sample of cognitively intact older adults: neuropsychological findings.
        Hum Psychopharmacol Clin Exp. 2002; 17: 267-277
        • Isaacsohn J.L.
        • Moser M.
        • Stein E.A.
        • Dudley K.
        • Davey K.
        • Liskov E.
        • et al.
        Garlic powder and plasma lipids and lipoproteins: a multicenter, randomized, placebo-controlled trial.
        Arch Int Med. 1998; 158: 1189-1194
        • Murphy L.S.
        • Reinsch S.
        • Najm W.I.
        • Dickerson V.M.
        • Seffinger M.A.
        • Adams A.
        • et al.
        Searching biomedical databases on complementary medicine: the use of controlled vocabulary among authors, indexers and investigators.
        BMC Complement Altern Med. 2003; 3: 3
        • McGregor B.
        Medical indexing outside the National Library of Medicine.
        J Me Libr Assoc. 2002; 90: 339-341
        • Kronenberg F.
        • Molholt P.
        • Zeng M.L.
        • Eskinazi D.
        A comprehensive information resource on traditional, complementary, and alternative medicine: toward an international collaboration.
        J Altern Complement Med. 2001; 7: 723-729
        • Pietri S.
        • Seguin J.R.
        • d'Arbigny P.
        • Drieu K.
        • Culcasi M.
        Ginkgo biloba extract (EGb 761) pretreatment limits free radical-induces oxidative stress in patients undergoing coronary bypass surgery.
        Cardiovasc Drugs Ther. 1997; 11: 121-131
        • Savulescu J.
        • Chalmer I.
        • Blunt J.
        Are research ethics committees behaving unethically? Some suggestions for improving performance and accountability.
        BMJ. 1996; 313: 1390-1393
        • Ho F.M.
        • Hunag P.J.
        • Lee F.K.
        • Chern T.S.
        • Chiu T.W.
        • Liau C.S.
        Effect of acupuncture at Nei-Kuan on left ventricular function in patients with coronary artery disease.
        Am J Chin Med. 1999; 27: 149-156
        • Xueping Z.
        • Zhongying Z.
        • Miaowen J.
        • Hong W.
        • Mianhua W.
        • Yaohong S.
        • et al.
        Clinical study of Qingluo Tongbi Granules in treating 63 patients with rheumatoid arthritis of the type yin-deficiency and heat in the collaterals.
        J Trad Chin Med. 2004; 24: 83-87
        • Johnson E.S.
        Feverfew: a traditional remedy for migraine and arthritis.
        Sheldon Press, London1984
        • Shelton R.C.
        • Keller M.B.
        • Gellenberg A.
        • Dunner D.L.
        • Hirschfeld R.
        • Thase M.E.
        • et al.
        Effectiveness of St. John's wort in major depression: a randomized controlled trial.
        JAMA. 2001; 285: 1978-1986
        • Roberts C.
        The implications of variation in outcome between health professionals for the design and analysis of randomized controlled trials.
        Stat Med. 1999; 18: 2605-2615
        • Dreikorn K.
        • Borkowsi A.
        • Braeckman J.
        • Denis L.
        • Ferrari P.
        • Gerber G.
        • et al.
        Other medical therapies.
        in: Denis L. Griffiths K. Khoury S. Cockett A.T.K. McConnell J. Chatelain C. Murphy G. Yoshida O. Proceedings of the 4th international consultation on benign prostatic hyperplasia (BPH). Plymbridge Distributors, Plymouth1998: 633-659
        • Dreikorn K.
        • Lowe F.
        • Borkowski A.
        • Buck C.
        • Braeckman J.
        • Chopin D.
        Other medical therapies.
        in: Chatelain Denis L. Foo K.T. Khoury S. McConnell J. Proceedings of the 5th international consultation on benign prostatic hyperplasia (BPH). Plymbridge Distributors, Plymouth2001: 479-511
        • Harkey M.R.
        • Henderson G.L.
        • Gershwin M.E.
        • Stern J.S.
        • Hackman R.M.
        Variability in commercial Ginseng products: an analysis of 25 preparations.
        Am J Clin Nutr. 2002; 75: 600-601
        • Gurley B.J.
        • Gardner S.F.
        • Hubbard M.A.
        Content versus label claims in ephedra-containing dietary supplements.
        Am J Health Syst Pharm. 2000; 57: 963-969
        • Liberti L.E.
        • Der Marderosian A.
        Evaluation of commercial ginseng products.
        J Pharm Sci. 1978; 67: 1487-1489
        • Groenewegen W.A.
        • Heptinstall S.
        Amounts of feverfew in commercial preparations of the herb.
        Lancet. 1986; 1: 44-45
        • Heptinstall S.
        • Awang D.V.
        • Dawson B.A.
        • Kindack D.
        • Knight D.W.
        • May J.
        • et al.
        Parthenolide content and bioactivity of feverfew (Tanacetum parthenium [L.] Schultz-Bip.). Estimation of commercial and authenticated feverfew products.
        J Pharm Pharmacol. 1992; 44: 391-395
        • Nelson M.H.
        • Cobb S.E.
        • Shelton J.
        Variations in parthenolide content and daily dose of feverfew products.
        Am J Health Syst Pharm. 2002; 59: 1527-1531
        • Zhang H.
        • Yu C.
        • Jia J.Y.
        • Leung S.W.
        • Siow Y.L.
        • Man R.Y.
        • et al.
        Contents of four active components in different commercial crude drugs and preparations of danshen (Salvia miltiorrhiza).
        Acta Pharmacol Sin. 2002; 23: 1163-1168
        • Manning J.
        • Roberts J.C.
        Analysis of catechin content of commercial green tea products.
        J Herb Pharmacother. 2003; 3: 19-32
        • Schulte-Lobbert S.
        • Holloubek G.
        • Muller W.E.
        • Schubert-Zsilavecz M.
        • Wurglics M.
        Comparison of the synaptosomal uptake inhibition of serotonin by St. John's wort products.
        J Pharm Pharmacol. 2004; 56: 813-818
        • Garrara J.
        • Hamrs S.
        • Eberly L.E.
        • Matiak A.
        Variations in product choices of frequently purchased herbs: caveat emptor.
        Arch Int Med. 2003; 163: 2290-2295
        • Weber H.A.
        • MK Zart
        • Hodges A.E.
        • Molloy H.M.
        • O'Brien B.M.
        • Moody L.A.
        • et al.
        Chemical comparison of goldenseal (Hydrastis canadensis L.) root powder from three commercial suppliers.
        J Agric Food Chem. 2003; 51: 7352-7358
        • Carlson M.
        • Thompson R.D.
        Liquid chromatographic determination of methylzanthines and catechins in herbal preparations containing guarana.
        J AOAC Int. 1998; 81: 691-701
        • Lefebvre T.
        • Foster B.C.
        • Drouin C.E.
        • Krantis A.
        • Livesy J.F.
        • Jordan S.A.
        In vitro activity of commercial valerian root extracts against human cytochrome P450 3A4.
        J Pharm Pharm Sci. 2004; 7: 265-273
        • Oberlies N.H.
        • Kim N.C.
        • Brine D.R.
        • Collins B.J.
        • Handy R.W.
        • Sparacino C.M.
        • et al.
        Analysis of herbal teas made from the leaves of comfrey (Symphytum officinale): reduction of N-oxides results in order of magnitude increases in the measurable concentration of pyrrolizidine alkaloids.
        Public Health Nutr. 2004; 7: 919-924
        • Haller C.A.
        • Duan M.
        • Benowitz Nl
        • Jacob P.
        Concentrations of Ephedra alkaloids and caffeine in commercial dietary supplements.
        J Anal Toxicol. 2004; 28: 145-151
        • Sievenpiper J.L.
        • Arnason J.T.
        • Leiter L.A.
        • Vuksan V.
        Variable effects of American ginseng: a batch of American ginseng (Panax quinquefolius L.) with a depressed ginsenoside profile does not affects postprandial glycemia.
        Eur J Clin Nutr. 2003; 57: 243-248
      2. Greuter W, Mcneill J, Barrie FR, Burdet HM, Demoulin V, Filgueiras TS, et al. International Code of Botanical Nomenclature (ST LOUIS CODE), adopted by the Sixteenth International Botanical Congress, St Louis, Missouri, July 1999. Available at (Accessed July 2004).

        • Pellati F.
        • Benvenuti S.
        • Margro L.
        • Melegari M.
        • Soragni F.
        Analysis of phenolic compounds and radical scavenging activity of Echinacea spp.
        J Pharm Biomed Anal. 2004; 35: 289-301
        • Vuksan V.
        • Sivenpiper J.L.
        • Wong J.
        • Xu Z.
        • Beljan-Zdravkovic U.
        • Arnason J.T.
        • et al.
        American ginseng (Panax quinquefolius L.) attenuates postprandial glycemia in a time-dependent but not dose dependent manner in healthy individuals.
        Am J Clin Nutr. 2001; 73: 753-758
        • Morgenstern C.
        • Biermann E.
        The efficacy of Ginkgo special extract Egb 761 in patients with tinnitus.
        Int J Clin Pharmacol Ther. 2003; 5: 188-197
        • Betz J.M.
        • Eppley R.M.
        • Taylor W.C.
        • Andrzejewski D.
        Determination of pyrrolizidine alkaloids in commercial comfrey products (Symphytum sp.).
        J Pharm Sci. 1994; 83: 649-653
        • Patora J.
        • Majda T.
        • Gora J.
        • Klimek B.
        Variability in the content and composition of essential oil from lemon balm (Melissa officinalis L.) cultivated in Poland.
        Acta Pol Pharm. 2003; 60: 395-400
        • Drew S.
        • Davies E.
        Effectiveness of Ginkgo biloba in treating tinnitus: double blind, placebo controlled trial.
        BMJ. 2001; 322: 1-6
        • Vuksan V.
        • Starva M.P.
        • Sivenpiper J.L.
        • Koo V.Y.Y.
        • Wong E.
        • Beljan-Zdravkovic U.
        • et al.
        American Ginseng improves glycemia in individuals with normal glucose tolerance: effect of dose and time escalation.
        J Am Coll Nutr. 2000; 19: 738-744
        • Swanson C.A.
        Suggested guidelines for articles about botanical dietary supplements.
        Am J Clin Nutr. 2002; 75: 8-10
      3. Instructions to authors. Phytomed Int J Phytother Phytopharmacol. Available at (accessed July 2004).

        • German Federal Institute for Drugs and Medical Device
        The complete German Commission E monographs: therapeutic guide to herbal medicines.
        Integrative Medicine Communications, Boston, MA1999
      4. Bauer R, Tittel G. Quality assessment of herbal preparations as a precondition of pharmacological and clinical studies. Phytomedicine 2000;26;2(3):193–8.

        • Association of Analytical Communities (AOAC)
        (Accessed Nov 1, 2004. Available at)
      5. American Herbal Pharmacopoeia.
        (Accessed Nov 1, 2004. Available at)
      6. United States Pharmacopoeia.
        (Accessed Nov 3, 2004. Available at)
        • Chan K.
        Some aspects of toxic contaminants in herbal medicines.
        Chemosphere. 2003; 52: 1361-1371
        • Murphy J.J.
        • Heptinstall S.
        • Mitchell J.R.A.
        Randomized double-blind placebo-controlled trial of feverfew in migraine prevention.
        Lancet. 1988; 2: 189-192
        • Vickers A.J.
        • de Craen A.J.M.
        Why use placebos in clinical trials? A narrative review of the methodological literature.
        J Clin Epidemiol. 2000; 53: 157-161
        • Palevitch D.
        • Earon G.
        • Carasso R.
        Feverfew (Tanacetum parthenium) as a prophylactic treatment for migraine: a double-blind placebo-controlled study.
        Phytother Res. 1997; 11: 508-511
        • Brinkhaus B.
        • Hummelsberger J.
        • Kohnen R.
        • Seufert J.
        • Hempen C.H.
        • Leonhardy H.
        • et al.
        Acupuncture and Chinese herbal medicine in the treatment of patients with seasonal allergic rhinitis: a randomized-controlled clinical trial.
        Allergy. 2004; 59: 953-960
        • Bent S.
        • Xu L.
        • Lui L.
        • Nevitt M.
        • Schneider E.
        • Tian G.
        • et al.
        A randomized controlled trial of a Chinese herbal remedy to increase energy, memory, sexual function and quality of life in elderly adults in Beijing, China.
        Am J Med. 2003; 115: 441-447
        • Johnson E.S.
        • Kadam N.P.
        • Hylands D.M.
        • Hylands P.J.
        Efficacy of feverfew as prophylactic treatment of migraine.
        BMJ. 1985; 291: 569-573
        • Piscitelli S.C.
        • Burstein A.H.
        Herb-drug interactions and confounding in clinical trials.
        J Herb Pharmacother. 2002; 2: 23-26
        • Pietri S.
        • Seguin J.R.
        • d'Arbigny P.
        • Drieu K.
        • Culcasi M.
        Ginkgo biloba extract (EGb 761) pretreatment limits free radical-induced oxidative stress in patients undergoing coronary bypass surgery.
        Cardiovasc Drugs Ther. 1997; 11: 121-131
        • Dowling E.A.
        • Redondo D.R.
        • Branch J.D.
        • Jones S.
        • McNabb G.
        • Williams M.H.
        Effect of Eleutherococcus senticosus on submaximal and maximal exercise performance.
        Med Sci Sports Exerc. 1996; 28: 482-489
        • Fletcher R.H.
        • Fletcher S.W.
        • Wagner E.H.
        Clinical epidemiology: the essentials.
        Lippincott, Philidelphia, PA1996
        • Gardner C.D.
        • Chatterjee L.M.
        • Carlson J.J.
        The effect of a garlic preparation on plasma lipid levels in moderately hypercholesterolemic adults.
        Atherosclerosis. 2001; 154: 213-220
      7. Annals of Internal Medicine. Information for authors.
        (Accessed January 10, 2001. Available at)