Wednesday 6 August 2008

Homeopathy in animals.

(this article was originally published in the excellent Skeptical Intelligencer journal)

Is its apparent effectiveness in animals proof of homeopathy's effectiveness?

Many reasons are offered as to why homoeopathy has not been accepted by the mainstream. The arguments range from alleged institutional apathy or lack of understanding to an active conspiracy excluding homoeopaths from mainstream medicine (Coulter, 1980). It is claimed that conventional practitioners are too lazy or incompetent to acquire the disciplines necessary to practice homoeopathy (Coulter 1980, Kent 1900). Pharmaceutical companies are accused, largely without evidence, of suppressing homoeopathy as they allegedly fear competition from a medical modality offering an inexpensive direct-to-patient mode of therapy. Underlying all these arguments is the tacit conviction that homoeopathy is effective; all that is needed is for people to understand it better.

To support this conviction evidence of variable quality is offered ranging from selected therapeutic trials to a vast range of equally selective anecdotal case reports.

A common argument against homoeopathy is that, given its implausible mode of action, many perceived responses to homoeopathy must be due to the placebo effect. Knowing this it is claimed by proponents that apparently positive results in groups such as very young children, or animals, where the placebo effect cannot operate, offer particularly compelling evidence of its validity. This article will show that the argument that apparent success in veterinary cases constitutes proof of the effectiveness of homoeopathy is simplistic and false.

Why bogus Veterinary therapies appear to work

According to Dr Harris Coulter “the use of homoeopathy in veterinary medicine is of particular interest because the psychosomatic factor in treatment is largely excluded” (Coulter 1980); Peter Adams states that, in the case of animal treatment, “the patient is not even aware of receiving any medication so the placebo effect can be discounted” (Adams, 1996); Gerhard Koehler asserts that responses in animals associated with the use of homoeopathy “…show how ridiculous it is to call homoeopathic treatment ‘suggestive’… it is the objective result which counts in this field” (Koehler 1986). If these (non-veterinary) authors are incorrect in their certainty and homoeopathy is no more effective than placebo whereas this might be of some occasional benefit in human medicine it offers no benefit to animals under treatment who, in reality, would be receiving no treatment at all. This has serious implications for animal welfare.

In his 1997 article Barry Beyerstein gave examples of errors & bias which could give the (false) impression that homoeopathy was able to successfully treat disease in humans. Many of the points he makes are equally valid when applied to veterinary medicine. So what are the explanations that may help counter the homoeopathic argument which usually goes along the lines of, “we had a dog with a rash which was cured by homoeopathy and he didn’t know what sort of treatment he was having so it can’t just be mind over matter, can it”?

1. The disease may have run its natural course.

The body is perfectly capable of dealing with the vast majority of illnesses without external assistance. Evolution has gifted us a powerful immune system and a variety of mechanisms to ameliorate or resolve a variety of diseases. Many organs are capable of regeneration following injury. The skin will grow into large deficits to heal with minimal scarring, the liver will regenerate to full function following massive damage, certain fractures will knit, often giving a functional result, without any form of fixation, the heart can maintain its output and function despite defects such as valvular insufficiency. Animals’ lack of the psychological problems associated with trauma in humans and their apparent resistance to pain mean that, in some instances, even major injuries and disease will resolve themselves naturally in time if medical or surgical intervention is withheld or unavailable.

Examples of conditions which can present as severe yet may resolve without active intervention include gastro-enteritis, cystitis and lower urinary tract disease in cats, certain types of pelvic fracture, vestibular disease (a profound but often temporary disturbance of the balance centre, often erroneously referred to as a ‘stroke’ for convenience), lameness caused by sprains or bruising, some abscesses in cats, upper respiratory tract infections (cat ‘flu’ and kennel cough) and mild spinal disease. In uncomplicated cases spontaneous recovery can appear almost miraculous. If homoeopathic remedies are given during the course of the disease it can be very hard to convince an observer that the homoeopathy was not directly responsible for the final outcome.

Not every case will resolve unaided however and many of the above conditions require veterinary treatment. The correct treatment of diseases known to be self limiting is geared towards offering palliative support, particularly pain relief. Clearly, if homoeopathy is used to the exclusion of conventional drugs although the end result may be similar because of the natural healing process, the animal will have undergone considerable suffering in the interim having been denied proper analgesia.

2. Many diseases have a waxing and waning course.

Allergic skin conditions are common in the dog and if due to environmental allergens will naturally have a seasonal course; for instance signs associated with a pollen allergy will improve during the months when the relevant plant is not in flower.

Addison’s disease results from an under active adrenal gland and is notorious for symptoms which are be extremely variable ranging from vague lethargy to haemorrhagic enteritis and which often improve temporarily without treatment.

The mast cell tumour is a skin cancer in dogs taking the form of initially small skin lumps which appear dormant for many months. If traumatised these lumps will produce large amounts of substances such as histamine resulting in a large, local swelling many times the size of the original tumour. Although spectacular in appearance these reactive zones will usually resolve spontaneously although the original cancer remains.

Juvenile lamenesses in dogs are a special group of conditions which can appear minor in the first year or so of life. Eventually after a series of relapses and remissions they may appear to resolve but if left untreated can lead to serious, even disabling joint disease in middle age.

Often treatment is sought by owners for their pets when signs are at their worse and this is often just the time in cyclical diseases when temporary remission occurs naturally. Intervention by a homoeopath at this stage will coincidentally be associated with improvement in symptoms creating a false impression of cure and possibly delaying early investigation and appropriate treatment to a stage when such treatment is too late to be effective.

3. Use of a provisional or working diagnosis.

Much as we might wish otherwise, inevitably, in veterinary medicine standards of diagnostic investigation are not always as rigorous as in the human medical field. Cost restraints and finite resources are limiting factors in many cases. This means that in general practice vets may make a presumptive, working diagnosis or short-list a number of possibilities based on limited evidence and treat accordingly.

So, for instance a lump between the toes of a dog could be either a cyst, an abscess or a tumour. If detailed diagnostics are not an option a practitioner may treat with antibiotics since a cyst will resolve spontaneously, a tumour will show no response, thus justifying the cost of investigation and an abscess may respond to antibiotics. So the treatment will be effective, appear to be effective or be ineffective depending on the true nature of the condition. The use of antibiotics in a case where infection is not confirmed is far from the ideal of evidence based medicine but is a practical necessity in some cases.

It can be seen that in the same case a completely ineffective remedy such as homoeopathy will also have a reasonable chance of being associated with a resolution thus creating the false impression that a cure has been effected, even that homoeopathy has cured cancer. The difference again, as in the previous section is that very often a conventional vet will provide pain relief while awaiting the outcome whereas no pain relief is afforded by homoeopathy.

4. Mis-diagnosis by Veterinary surgeon, owner or owner’s friend.

Interpretation of the clinical examination, imaging techniques or laboratory analysis is not always cut and dried. There are very few conditions for which there is one completely certain diagnostic sign, most diagnoses rely on a multitude of tests as well as one’s clinical impression. So even trained professionals will occasionally make a mis-diagnosis. A good practitioner will work with this possibility always in mind, continually reviewing the case in the light of new information and re-appraising the diagnosis accordingly. A recent case of mine involved the removal of several suspect skin masses in a dog. Initial laboratory analysis suggested cancer. This didn’t concur with my clinical impression and following a conversation with the pathologist the findings were reinterpreted in the light of more detailed information as being the result of harmless inflammation. The owner, however, having had the provisional results, had self-referred to a Veterinary homoeopath who set about treating the cancer and incidentally a self limiting post-operative swelling called a seroma homeopathically. Needless to say treatment of the seroma was completely “successful”; whether, having been informed of the revised laboratory report, he also claimed a cure for cancer I don’t imagine I will ever know with an certainty.

The tendency of owners to self diagnose or to trust the diagnosis of acquaintances who may have had a pet with similar symptoms greatly adds to the potential number of mis-diagnoses and consequently to the number of apparent ‘miracle cures’. For instance a dog with a cough due to a viral infection may present very similarly to a dog in the initial stages of heart disease. If the owner of the dog with the viral infection is told by the owner of the dog with heart disease that their dog has the same condition and will deteriorate rapidly, requiring extensive investigations and treatment and the viral dog is treated homeopathically then, when the viral infection self cures in a week or two; behold, a miracle, homoeopathy has cured a failing heart.

5. Concurrent use of conventional medicine

This, so called “complementary medicine”, can be the most galling of all to the genuine practitioner when homoeopathy, used concurrently with conventional medicine, is credited entirely with the cure. This is particularly likely in the case of a condition that is slow to respond to treatment. After some time on conventional treatment the owner, concerned about the apparent lack of response will turn to a homeopath who initiates treatment which is immediately followed by a cure. Again, once this course of events has taken place it is well nigh impossible to persuade someone that the homoeopathy was irrelevant to the outcome and had they simply allowed further time the final result would have been the same.

6. A desire to believe on the part of owner and homeopath

Even when there are few if any improvements in the homeopathically treated animal, owners who have a strong psychological investment in alternative medicine can convince themselves they and their animal have been helped. To have received no relief after committing time and money to, and having a deep, personal belief in alternative treatment is difficult to admit to oneself and others so there is strong pressure to find some redeeming value in the treatment and avoid losing face. There may also be an unspoken complicity between owner and practitioner with neither party willing to disappoint the other with negative findings or comments. Of course an animal cannot make an informed choice and plays no part in this cosy conspiracy; it will either get better in spite of or suffer as a result of their owner’s dogma.


The veterinary profession has a reputation for being a caring one, I feel this reputation is deserved. The vast majority of vets that one meets are deeply committed to their clients and patients, human and animal, and have a strong desire to do their best for them, occasionally at personal cost.

It is a subject of continual debate amongst veterinary sceptics as to why colleagues who have had a scientific education and who might be expected to know better have turned to a treatment modality that has more to do with religious faith than rational medicine.

The more charitable among us will argue that in some cases this desire to help in the face of limited resources and failure to keep up with current thinking may be a reason why some have abandoned the uncertainties of the scientific path in favour of the more prescriptive homoeopathy. Possibly also a lack of humility makes it difficult for some people to admit they may have been wrong and to review their work critically. After all it is easier to tell oneself and one’s client that the skin condition is getting worse because of a ‘healing crisis’ rather than because of an error in diagnosis or, worse still because the medical modality you have invested so much of yourself in is completely false.

Others will argue that, given a veterinary education and even a basic knowledge of statistics and research, veterinary homoeopaths are guilty of at best turning a ‘mental blind eye’ to the inconsistencies of their calling and at worst of a disingenuous misinterpretation of the facts particularly by the blurring of the distinction between an improvement being associated with and being caused by a particular treatment.

Whatever the reason it is a great deal to expect homoeopathic practitioners with deep seated faith in homoeopathy with its quasi religious overtones to suddenly admit the error of their ways and change overnight. The effort is worthwhile however, my patients have no say in the matter of medical dogma, they are “dumb” animals and are entirely dependent on their human masters to make the right decisions for them. When the good sense of their carers is distorted, lacking or simply ill informed it is our duty to try to persuade and educate, gently and patiently, until reason prevails.

Adams, P., (1996) Natural medicine for the whole person (reissued 1998), Element books ltd, Shaftesbury
Beyerstein, B.L., (September/October 1997) Why bogus therapies seem to work, Skeptical Inquirer magazine
Coulter, H. L., (1980) Homoeopathic science and modern medicine, North Atlantic books, California.
Kent, J.T., (1900) Lectures on homoeopathic philosophy (1990 reprint of 1954 edition), B. Jain publishers ltd, New Delhi
Koehler, G., (1986) The handbook of homoeopathy, Thorson’s publishing group, Wellingborough

Useful reading:
Renan Moritz V. Rodrigues Almeida, (Federal University of Rio de Janeiro) Revista do Hospital das Clínicas vol.58 no.6 São Paulo 2003 (
Kleijnen, J., P. Knipschild and G. ter Riet. 1991. Clinical Trials of Homoeopathy. British Medical Journal; 302: 316-23
Hill, C. and F. Doyon. 1990. Review of Randomized Trials of Homoeopathy. Review D'Epidemilogie et de Sante Publique; 38: 139-147
Linde, Klaus, Nicola Clausius, Gilbert Ramirez, Dieter Melchart, Florian Eitel et al. 1997. Are the Clinical Effects of Homoeopathy Placebo Effects? A Meta-Analysis of Plecebo-Controlled Trials. Lancet, 350: 834-43
Ernst, E. and M.H. Pittler, Journal of Clinical Epidemiology 53 (2000) 1188, Re-analysis of previous meta-analysis of clinical trials of homeopathy
Linde et al, Impact of Study Quality on Outcome in Placebo-Controlled Trials of Homeopathy, J Clin Epidemiol Vol. 52, No. 7, pp. 631–636, 1999
Boissel, J.P., M. Cucherat, M. Haugh and E. Gauthier. Critical Literature Review on the Effectiveness of Homoeopathy: Overview of Data from Homoeopathic Medicine Trials. In Homoeopathic Medicine Research Group. Report. Commission of the European Communities
Cucherat M, Haugh MC, Gooch M, Boissel JP Eur J Clin Pharmacol 2000 Apr;56(1):27-33 Evidence of clinical efficacy of homeopathy. A meta-analysis of clinical trials.


  1. Hello! Nice article.

    I have been discussing this issue in where I have been offered a link to In this study it says that "The discrepancies between single-blind and double-blind methods in animal pharmacological research are noteworthy and should be better investigated, also in non-homeopathic research."

    I´m not sure what to understand from this, but it seems that rats do heal better when the experimenters who administer the remedies know whether they are giving them a real remedy or a placebo. And in this case it doesn´t seem to be a case of the experimenters perceiving the data differently due to lack of blinding, because the ones who take the measure are blinded AFAICS.

    I´would like to know what you think of this, I probably have it all wrong but I can´t see why...

    Thank you!

  2. Hi Mikel,

    Thanks for your kind words about the article.

    The thing about the rat experiment isn't that rats heal at a different rate depending on whether the experimenters were 'blinded' or not, there's no way that could make any difference. What the results do suggest strongly is that there is still experimenter bias with a single blinded protocol which isn't apparent in a double blinded one.

    There must have been some 'leakage' of information between the people doing the measuring (blinded) and those adminitering the remedies (unblinded). They may have talked about it, there may have been tell-tale signs in the rat cages or it could have been even more subtle like body language between the two groups of technicians. Either way the paper shows how important it is to have a protocol double blinded to rule out experimenter bias. Mere single blinding just isn't up to the job.

    You should be highly suspicious of any paper which states an experiment was "blinded"; if they don't specify "double" blinded you can be pretty sure the protocol was inadequate and any results regarded with suspicion.