Clinical trials

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Clinical trials are experiments carried out on patients to compare the effects of two or more treatments under highly controlled conditions. One type of clinical trial – the randomised controlled trial (RCT) – is considered by many scientists to be the ‘gold standard’ of research methods for determining whether medical treatments are effective. RCTs have been used to investigate various different aspects of homeopathy, such as how homeopathic medicines compare with placebo and how effective homeopathic treatment is for specific conditions.

Systematic reviews (assessments of the total research evidence available on a particular subject, designed to provide more accurate information than single studies) have also been carried out to draw firmer conclusions.

The following topics are covered on this page:

Summary of randomised controlled trials

By the end of 2010, 156 RCTs of homeopathy (covering 75 medical conditions) had been published in good quality journals. In terms of statistically significant results, 75 of these trials were able to draw firm conclusions:

  • 64 were positive
  • 11 were negative*

The fact that the remaining 81 trials were inconclusive highlights the need for changes in the way homeopathy research is conducted in future to generate meaningful results. Two key factors are the need for larger scale trials (commonly prevented by a lack of funding) and the use of more appropriate research methods such as pragmatic trials, which are better-suited to the task of testing a complex individualised therapy such as homeopathy.

*data courtesy of the Faculty of Homeopathy

To download ‘Medical conditions with positive balance of evidence in homeopathy’ – a comprehensive list of positive trials investigating specific medical conditions prepared by the British Homeopathic Association – click here

To download more information about the future of homeopathy research click here

Evidence for specific conditions

Randomised controlled trials have been carried out to investigate the efficacy or effectiveness of homeopathic medicine in 75 specific medical conditions but more work of this nature is needed to assess the possible value of homeopathy across a wider range of illnesses. To date, conditions for which the majority of clinical trial findings have been positive include:

Allergies and upper respiratory tract infections

Evidence: Systematic review

Bornhoft G, Wolf U, Ammon K, et al. Effectiveness, safety and cost-effectiveness of homeopathy in general practice – summarized health technology assessment. Forsch Komplementarmed 2006; 13 (2): 19-29

Ankle sprain

Evidence: One un-refuted RCT

Zell J, Connert WD, Mau J, Feuerstake G. Treatment of acute sprains of the ankle. Controlled double-blind trial to test the effectiveness of a homeopathic ointment. Fortschr Med 1988; 106: 96-100

Bowel inactivity after surgery (post-operative ileus)

Evidence: Systematic review

Barnes J, Resch K-L, Ernst E. Homeopathy for postoperative ileus? A meta-analysis. J Clin Gastroenterol 1997; 25: 628-33


Evidence: One un-refuted RCT

Diefenbach M, Schilken J, Steiner G, Becker HJ. Homeopathic therapy in respiratory tract diseases. Evaluation of a clinical study in 258 patients. Z Allgemeinmed 1997; 73: 308-14

Childhood diarrhoea

Evidence: Systematic review

Jacobs J, Jonas WB, Jimenez-Perez M, Crothers D. Homeopathy for childhood diarrhea: combined results and metaanalysis from three randomized, controlled clinical trials. Pediatr Infect Dis J 2003; 22: 229-34

Chronic Fatigue

Evidence: One un-refuted RCT

Weatherley-Jones E, Nicholl JP, Thomas KJ, et al. A randomized, controlled, triple-blind trial of the efficacy of homeopathic treatment for chronic fatigue syndrome. J Psychosom Res 2004; 56: 189-97

Ear infections (acute otitis media)

Evidence: One un-refuted RCT

Jacobs J, Springer DA, Crothers D. Homeopathic treatment of acute otitis media in children: a preliminary randomized placebo-controlled trial. Pediatr Infect Dis J 2001; 20: 177-83


Evidence: Two or more RCTs

Fisher P. An experimental double-blind clinical trial method in homoeopathy. Use of a limited range of remedies to treat fibrositis. BrHomeopath J 1986; 75: 142-7

Bell I, Lewis D, Brooks A, et al. Improved clinical status in fibromyalgia patients treated with individualized homeopathic remedies versus placebo. Rheumatology 2004; 43: 577-82

Relton C, Smith C, Raw J, Walters C, Adebajo AO, Thomas KJ. Healthcare provided by a homeopath as an adjunct to usual care for Fibromyalgia (FMS): results of a pilot Randomised Controlled Trial. Homeopathy, 2009; 98: 77-82.

Hay fever (seasonal allergic rhinitis)

Evidence: Systematic reviews

Wiesenauer M, Ludtke R. A meta-analysis of the homeopathic treatment of pollinosis with Galphimia glauca. Forsch Komplementarmed Klass Naturheilkd 1996; 3: 230-6

Taylor MA, Reilly D, Llewellyn-Jones RH, et al. Randomised controlled trials of homoeopathy versus placebo in perennial allergic rhinitis with overview of four trial series. Br Med J 2000; 321: 471-6

Bellavite P, Ortolani R, Pontarollo F, et al. Immunology and homeopathy. 4. Clinical studies – Part 2. eCAM 2006; 3: 397-409.

Influenza treatment

Evidence: Systematic review

Vickers A, Smith C. Homoeopathic Oscillococcinum for preventing and treating influenza and influenza-like syndromes (Cochrane Review). In: The Cochrane Library. Chichester, UK: John Wiley & Sons, Ltd. 2006


Evidence: Two or more RCTs

Shealy CN, Thomlinson RP, Cox RH, Borgmeyer RN. Osteoarthritic pain: a comparison of homeopathy and acetaminophen. Am J Pain Manage 1998; 8: 89-91

van Haselen RA, Fisher PAG. A randomized controlled trial comparing topical piroxicam gel with a homeopathic gel in osteoarthritis of the knee. Rheumatology 2000; 39: 714-9

Premenstrual syndrome

Evidence: One un-refuted RCT

Yakir M, Kreitler S, Brzezinski A, et al. Effects of homeopathic treatment in women with premenstrual syndrome: a pilot study. Br Homeopath J 2001; 90: 148-53

Rheumatic diseases

Evidence: Systematic review

Jonas WB, Linde K, Ramirez G. Homeopathy and rheumatic disease – Complementary and alternative therapies for rheumatic diseases II. Rheum Dis Clin North Am 2000; 26: 117-23


Evidence: Two or more RCTs

Friese K-H, Zabalotnyi DI. Homeopathy in acute rhinosinusitis. A double-blind, placebo controlled study shows the effectiveness and tolerability of a homeopathic combination remedy. HNO 2007; 55: 271-7

Zabolotnyi DI, Kneis KC, Richardson A, et al. Efficacy of a complex homeopathic medication (Sinfrontal) in patients with acute maxillary sinusitis: a prospective, randomized, doubleblind, placebo-controlled, multicenter clinical trial. Explore (NY) 2007; 3: 98-109


Evidence: Systematic review

Schneider B, Klein P, Weiser M. Treatment of vertigo with a homeopathic complex remedy compared with usual treatments: a meta-analysis of clinical trials. Arzneimittelforschung 2005; 55: 23-9

As homeopaths treat the whole person rather than individual diseases, it can appear contradictory to have research trials testing homeopathic treatment of specific medical conditions, but there are good reasons why researchers work through this apparent clash of philosophies to contribute to the evidence base for homeopathy.

Holistic medicine versus disease labels – a clash of philosophies?

Homeopathy is a holistic therapy, treating the person as a whole rather than treating specific diseases. This is one of the main differences between homeopathy and conventional medicine. For example, if you are suffering from anxiety, arthritis and a skin condition the conventional route might involve entirely separate courses of treatment from a psychologist, rheumatologist and dermatologist; by contrast a homeopath would consider all of these mental-emotional and physical symptoms to be linked and therefore treat them as a whole.

However, even in complicated cases such as this where there are multiple health problems the person will usually ask the homeopath for help with one particular condition which is bothering them the most. This ‘presenting complaint’ or ‘chief complaint’ identified at the first appointment can be used to allocate someone to a clinical trial investigating homeopathic treatment of that condition.

There are three main reasons why homeopathy researchers are gathering evidence from trials assessing how effective homeopathic treatment is for specific diseases:

1. Patients considering seeing a homeopath often ask whether homeopathy can help with their chief complaint

2. When another medical professional refers a patient to a homeopath they may want to know what track record the therapy has in treating that specific disease

3. The NHS provides the majority of medical services according to disease categories so for homeopathy to be included in the range of services offered – e.g. in a rheumatology department – research needs to demonstrate that homeopathic treatment is effective in treating fibromyalgia, osteoarthritis etc.

Research in homeopathy is a wide field and this is just one of many different avenues being pursued by researchers world-wide to build on the evidence base for homeopathy.

For more examples of positive trials please see the Research Downloads page (click here).

Comparing homeopathy and conventional medicine

Research studies comparing homeopathic treatment and conventional care have generated some interesting results.

For example it has been found that:

Treatment by a homeopath can be more effective than conventional treatment for acute ear infections in children [2]:

  • This study published in the International Journal of Clinical Pharmacology and Therapeutics concluded that homeopathy should be the first line treatment for acute ear infections in children. The group of 103 children who received individualised homeopathic treatment had faster pain relief during the initial infection and fewer ear infections over the following year, compared with the children who received conventional treatment.
  •  Friese K-H, et al. Homeopathic treatment of otitis media in children: comparisons with conventional therapy. Int J Clin Pharmacol Ther, 1997; 35: 296-301.

Homeopathic medicines may be superior to a standard pain killer for relieving pain in osteoarthritis [3]:

  • In this double-blind* trial 65 sufferers of Osteoarthritis (OA) were split into 2 groups were given either a homoeopathic medicine or Acetaminophen, a commonly prescribed drug for pain relief in OA. Researchers found that homoeopathy provided a level of pain relief that was superior to Acetaminophen, and produced no adverse reactions
  • To minimise bias, neither the researchers nor the participants knew what treatment each person was given

Treatment by a homeopath is just as effective as fluoxetine (Prozac) for acute moderate-severe depression [4]:

  • This double-blind* randomised controlled trial carried out in Brazil involved 91 patients – half received fluoxetine and half received individualised treatment by a homeopath.
  • To minimise bias, neither the researchers nor the participants knew what treatment each person was given.
  •  Adler UC, et al. Homeopathic Individualized Q-potencies versus Fluoxetine for Moderate to Severe Depression: Double-blind, Randomized Non-inferiority Trial. eCAM, 2009

Systematic reviews

A systematic review is a summary of the total research evidence available on a particular subject, designed to provide more reliable information than single studies. Specific methods are used to search academic journals and identify which studies are suitable for inclusion in the review (e.g. those of suitably high quality). From these identified trials a smaller number may be found suitable to go into a meta-analysis (meta-analysis = A statistical technique used to analyse the combined results of multiple studies to generate a more meaningful overall result).

Five major systematic reviews have been carried out to analyse the balance of evidence from RCTs of homeopathy – four were positive and one was negative:

Conclusion: Homeopathy is more effective than placebo
Kleijnen et al. 1991 105 trials identified; results based on 105 trials.[5]

Authors’ Comments:

“The evidence presented in this review would probably be sufficient for establishing homeopathy as a regular treatment for certain indications. There is no reason to believe that the influence of publication bias, data massage, bad methodology, and so on is much less in conventional medicine, and the financial interests for regular pharmaceutical companies are many times greater.”

Linde et al. 1997 186 trials identified; results based on 89 trials.[6]

Authors’ Comments:

“The results of our meta-analysis are not compatible with the hypothesis that the clinical effects of homeopathy are completely due to placebo. However, we found insufficient evidence from these studies that homeopathy is clearly efficacious for any single clinical condition.”

Linde et al. 1999 Re-analysis of same data but low quality trials excluded. Smaller but still significant difference found between homeopathy and placebo.[7]

Authors’ Comments:

“We conclude that in the study set investigated, there was clear evidence that studies with better methodological quality tended to yield less positive results.”

Cucherat et al. 2000 118 trials identified; results based on 16 trials.[8]

Authors’ Comments:

“There is some evidence that homeopathic treatments are more effective than placebo; however, the strength of this evidence is low because of the low methodological quality of the trials.”

Conclusion: Homeopathy is no more effective than placebo Shang et al. 2005

110 homeopathy trials identified; results based on 8 trials.
110 conventional medicine trials identified; results based on 6 trials.[9]

Authors’ Comments

“Biases are present in placebo-controlled trials of both homeopathy and conventional medicine. When account was taken for these biases in the analysis, there was weak evidence for a specific effect of homeopathic remedies, but strong evidence for specific effects of conventional interventions. This finding is compatible with the notion that the clinical effects of homeopathy are placebo effects.”

Common findings throughout these studies included problems with variable trial quality, variable trial design, publication bias (publication bias = Tendency for studies with a positive result to be published more readily than those which are negative or inconclusive) and the small number of studies available in total. Despite these limitations, four of the five reviews found that even high quality trials produced positive results in favour of homeopathy. The authors called for more research with a focus on the role of homeopathy in the treatment of specific disease conditions and an emphasis on larger, high quality studies.

The most recent review by the Swiss team of Shang et al. was published in the Lancet alongside an editorial entitled ‘The End of Homeopathy’. This understandably sparked an intense media debate. The study now lacks credibility since scientists worldwide have drawn attention to serious flaws in how the study was conducted and how the results were presented.[10], [11], [12]. Most notably the study does not meet the ‘quality-control’ criteria for publication of meta-analyses as described in the Lancet itself in 1999.[13]

Systematic reviews should be ‘transparent and reproducible’ (Ernst, 2007) yet the initial study gave no information about which trials had been used in the analysis. This is unacceptable in scientific publications. When the necessary information was finally released allowing other researchers to replicate the study, a team produced two articles challenging Shang’s findings, describing flaws which make the results unreliable (Ludtke 2008, Rutten 2008).

Ernst E. Understanding Research in Complementary and Alternative Medicine. Holistic Therapy Books, 2007

Ludtke R, Rutten ALB. The conclusions on the effectiveness of homeopathy highly depend on the set of analyzed trials. J Clin Epidemiol, 2008

Rutten ALB, Stolper CF. The 2005 meta-analysis of homeopathy: the importance of post-publication data. Homeopathy, 2008

A small number of systematic reviews have confirmed that homeopathy can be effective for specific conditions, but more research of this kind is needed to investigate a wider range of conditions.

Limitations of systematic reviews

Systematic reviews# are intended to draw conclusions from data collected from multiple similar studies, yet the set of trials used in reviews of homeopathy vary widely in both the type of homeopathic treatment given and the medical conditions being investigated.

#Systematic reviews = The need for clarity

The term ‘homeopathy’ is used with several different meanings in the context of homeopathy research.* This means that studies investigating very different approaches are all described as trials of ‘homeopathy’ and are frequently analysed together in systematic reviews e.g.:

A standard single homeopathic medicine given to all participants

A standard combination of several homeopathic medicines given to all participants

Individualised prescribing without a homeopathic consultation

Treatment by a homeopath including individualised prescription and consultation

Isopathic trials e.g. homeopathic pollen for treatment of hay fever

For future homeopathy research to be meaningful, specific definitions within the umbrella term of ‘homeopathy’ are needed to promote clarity in the reporting, design and interpretation of homeopathy research i.e. stating whether a trial is investigating treatment by a homeopath, the action of a homeopathic medicine or the principles of homeopathy.’

* Relton C et al. ‘Homeopathy’: Untangling the debate. Homeopathy, 2008; 97: 152-5


1. Mathie, R. The Research Evidence Base for Homeopathy. British Homeopathic Association, 2009.

2. Friese K-H, et al. Homeopathic treatment of otitis media in children: comparisons with conventional therapy. Int J Clin Pharmacol Ther, 1997; 35: 296-301

3. Shealy C.N., Thomlinson P.R., Cox R.H., and Bormeyer V. Osteoarthritis Pain: A Comparison of

Homoeopathy and Acetaminophen. American Journal of Pain Management, 1998; 8 (3): 89-91

4. Adler UC, et al. Homeopathic Individualized Q-potencies versus Fluoxetine for Moderate to Severe Depression: Double-blind, Randomized Non-inferiority Trial. eCAM, 2009

5. Kleijnen J, et al. Clinical trials of homeopathy. Br Med J, 1991; 302: 316–23

6. Linde K, et al. Are the clinical effects of homoeopathy placebo effects? A meta-analysis of placebo-controlled trials. Lancet, 1997; 350: 834–43

7. Linde K, et al. Impact of study quality on outcome in placebo controlled trials of homeopathy. J Clin Epidemiol, 1999; 52: 631–6

8. Cucherat M, et al. Evidence of clinical efficacy of homeopathy – A meta-analysis of clinical trials. Eur J Clin Pharmacol, 2000; 56: 27–33

9. Shang A, et al. Are the clinical effects of homoeopathy placebo effects? Comparative study of placebo-controlled trials of homoeopathy and allopathy. Lancet, 2005; 366: 726–32

10. Bell, I. All Evidence is Equal, but Some Evidence is More Equal than Others: Can Logic Prevail over Emotion in the Homeopathy Debate? 2005, JACM, 11(5): 763-9

11. Frass, M et al. Bias in the Trial and Reporting of Trials of Homeopathy: A Fundamental Breakdown in Peer Review and Standards? JACM, 2005, 11(5): 780-2

12. Helmut K, et al. Failure to Exclude False Negative Bias: A Fundamental Flaw in the Trial of Shang et al. JACM, 2005; 11(5): 783

13. Moher D, et al. Improving the quality of reports of meta-analyses of randomised controlled trials: the QUOROM statement. Quality of Reporting of Meta-analyses. Lancet, 1999; 354(9193):1896-900