Ethics and Evidence-based Medicine

The relationship between evidence-based medicine (EBM) and ethics may not be immediately apparent. EBM focuses on facts and data, safety and efficacy, and determining what we know and don’t know. Veterinary ethics is about what is right or wrong to do in the context of veterinary practice. The values that inform ethical principles are subjective and not always shared between individuals or different segments of the profession. The evidence used to evaluate the safety and efficacy of medical treatments, in contrast, should ideally be produced by methods broadly agreed to be the most objective and reliable possible. However, EBM turns out to be a key tool for achieving ethical clinical practice.

Despite inevitable controversy and disagreement, there are some ethical principles broadly accepted by most veterinarians. Some of these are articulated in statements such as the American Veterinary Medical Association’s Principles of Veterinary Medical Ethics.1 This document was adapted from the principles established for physicians by the American Medical Association, and similar statements have been adopted by veterinary associations around the world.2-6

Other widely accepted ethical standards are simply common elements of more basic cultural norms. For example, most of us would likely agree that we should try to help our patients and our clients, we should be honest with clients, and we should do our best to be technically competent and familiar with the current scientific knowledge that underlie clinical medicine.

These basic ethical precepts are formalized in the domain of medical ethics as several core principles, which usually include:

Beneficence–  Clinicians should attempt to help their patients, to benefit them.7

Non-maleficence– Clinicians should attempt to avoid harming their patients or to do more good than harm.7

Autonomy– Patients (or in veterinary medicine, their owners) have the right to accept or reject treatment. This is the foundation for the more specific concept of informed consent.7

Informed Consent– Clients have the right to make choices about the treatment of their animals based on accurate, relevant information they can understand.8

So what does EBM have to do with meeting these ethical obligations? Well, ethical judgements cannot be made without facts. The best path to abide by one’s ethical principles cannot be determined without an accurate understanding of the context. EBM informs ethical practice by giving us, and our clients, an accurate understanding of the risks and benefits of our actions as well as the degree of uncertainty about these.

In terms of beneficence and non-maleficence, for example, one cannot successfully help patients and minimize harm without an accurate understanding of the causes of disease and the effects of our treatments. If we attribute illness to the wrong cause, we are unlikely to stumble across an effective remedy. And if our treatments don’t actually work, or if they have risks that we are not aware of, then we are less able to do good and avoid harm to our patients.

Similarly, we deny clients their right to informed consent if we give them incorrect information about diagnosis, prognosis or the likely outcome of our treatments. This is equally true whether we are deliberately lying or are simply mistaken. The history of medicine is a long, frightening tale of incorrect beliefs about disease and of ineffective, even harmful treatments enthusiastically applied by well-meaning doctors. We are no smarter or better intentioned than our predecessors, but thanks to science, we are better informed.

Evidence-based medicine, then, is arguably a necessary component to ethical veterinary practice. It serves to provide clinicians with the most current and accurate understanding of the causes of disease and the risks and benefits of our therapies. EBM also helps us quantify the inevitable uncertainties we must accept and communicate to our clients.

There is rarely optimal evidence, so the most conscientious practitioner of EBM will often not be able to accurately predict the outcome of his or her treatments. However, even in this situation, EBM is useful because it supports truly informed consent. If the evidence supporting a particular therapy is weak, I may well still offer that therapy. However, I am able, even obligated, to understand the limitations of the evidence and share this with the client to help support informed decision making.8

There is often anxiety among veterinarians about disclosing uncertainty to clients. We fear they may not trust in our competence or may eschew beneficial treatment if we express any uncertainty or discuss the limitations of our knowledge. However, there is evidence that may allay this anxiety. Surveys have shown that clients expect to be told about the uncertainty associated with our recommendations and that they do not lose confidence in us as a result.9 Even more significant from an ethical perspective, clients in one study emphasized that their central expectation for the information they were given by their veterinarians was that it be the truth.10 EBM helps us meet the ethical obligation and client expectation that we communicate truthfully about our recommendations and our uncertainty.

So far, this idea that EBM can facilitate ethical veterinary practice by giving us the most accurate information and helping us measure our uncertainty may not seem especially controversial. Unfortunately, if we commit to EBM as the best source of information to support effective and ethical medicine, we eventually enter more tendentious territory.

For example, EBM includes the presumption that some sources of evidence are more reliable than others.11-12 This often leads to a conflict between what we believe, based on anecdote or personal experience, and what scientific evidence supports. Clinicians dislike being told that therapies which seem and effective in use are either scientifically unproven or have significant evidence against their safety or effectiveness. Yet our obligation to be informed and competent, and to provide accurate and truthful information to clients, can sometimes mean accepting the unreliability of anecdotal experiences, even our own.

An even more contentious topic is the ethical appropriateness of theoretical systems and treatment methods with core principles that conflict with established science. Much of what is often called alternative medicine consists of beliefs about the causes of illness and methods of treatment that are either scientifically unproven or even demonstrably incorrect based on research evidence.13-14 Alternative medicine raises many complex ethical issues,15 and it has been argued, in both human and veterinary medicine, that the use and sale of such approaches, however honest and well-intentioned, violate some broadly held ethical principles.14-19

Informed consent and autonomy are denied when clients are given information about their animals’ health that is inaccurate by the best available standards of evidence and scientific consensus. Beneficence and nonmaleficence cannot be maintained if ineffective treatments are offered.16

Often of course, there are legitimate disagreements about the meaning or strength of the evidence. However, there must be some generally accepted standard of proof required beyond simply the personal belief of the individual clinician to justify our treatments. If not, then there is no purpose to the systems of licensing and regulation intended to protect the public from unsafe and useless medical treatment. The caveat emptor free-for-all of medicine in the 18th and 19th centuries was ultimately rejected in the 20th as unsafe, and this was predicated on the belief that scientific evidence could provide a common basis for evaluating medical practice. This is a key pillar of the ethical structure of modern medicine, and EBM is an important tool for supporting ethical, science-based practice.


  1. AVMA Principles of Veterinary Medical Ethics. Available at: Accessed January 31, 2018.
  2. AMA Principles of Medical Ethics. Available at: Accessed Access on January 31, 2018.
  3. CVMA. Principles of Veterinary Medical Ethics. Available at: Accessed January, 31, 2018.
  4. FVE. European Veterinary Code of Conduct. Available at: Accessed on January 31, 2018.
  5. AVA. Code of Professional Conduct. Available at: Accessed January 31, 2018.

6.Veterinary Council of India. Code of Ethics. Available at: Accessed January 31, 2018.

7.Beauchamp TL. Childress JF. Principles of biomedical ethics. 5th Ed. (2001) New York, NY: Oxford University Press.

  1. Fettman MJ. Rollin BE. Modern elements of informed consent for general veterinary practitioners. J Amer Anim Hosp Assoc. 2002;221(10):1386-1393.
  2. Mellanby RJ. Crisp J. De Palma G. et al. Perceptions of veterinarians and clients to expressions of clinical uncertainty. J Small Anim Pract. 2007;48(1):26-31.


  1. Stoewen DL. Coe JB. MacMartin C. et al. Qualitative study of the information expectations of clients accessing oncology care at a tertiary referral center for dogs with life-limiting cancer. J Amer Vet Med Assoc. 2014;245(7):773-83.
  2. McKenzie B. A new perspective on evidence-based medicine. Vet Pract News. July, 2017. Available at: Accessed January 31, 2018.
  3. Cockroft, P. Holmes, M. (2003). Handbook of Evidence-Based Veterinary Medicine. Oxford: Blackwell.
  4. McKenzie, BA. Is complementary and alternative medicine compatible with evidence-based medicine? J Amer Vet Med Assoc. 2012;241(4):421-6.
  5. Ramey, DW. Rollin, BE. (2004). Complementary and Alternative Veterinary Medicine Considered. Ames: Iowa State Press.
  6. Nuffield Council on Bioethics. Complementary medicine: ethics. 2014. Available at: Accessed January 31, 2018
  7. Smith K. Against homeopathy-A utilitarian perspective.Bioethics2012;26(8):398–409.


  1. Ernst E. Cohen MH. Stone J. Ethical problems arising in evidence based complementary and alternative medicine. J Med Ethics. 2004;30:156-9.


  1. Milstein M. The case against alternative medicine. Can Vet J. 2000;41:769-72.


  1. Macdonald C. Gavura S. Alternative medicine and the ethics of commerce. Bioethics, 30: 77–84.


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7 Responses to Ethics and Evidence-based Medicine

  1. Jodi Ware says:

    Absolutely! Positively! I couldn’t agree more. Thank you, skeptvet, for writing this piece, and thank you, Veterinary Practice News, for also publishing it!

  2. Jazzlet says:

    Personally I would always prefer a doctor or vet who admitted ignorance than one who insisted they knew everything then turned out to be wrong. The has former happened several times with vets and doctors, most recently a couple of months ago with my GP (PCP). She didn’t know if a drug (duloxetine) prescribed for two purposes (antidepressant and pain blocker) would treat one of them preferentially if that got worse leaving the other untreated, which is what seemed to be happening. It reassured me that she was quite happy to admit she didn’t know and to hear that she would seek the advice of a specialist on how to proceed, after all she is a general practitioner who shouldn’t be expected to know everything. I have also had the latter when a specialist assured me there was nothing wrong with me, only to find that there was a major problem and that was a very unsettling experience which, understandably I think, left me with no confidence in his competance. So having experienced both approaches I know which I prefer!

  3. skeptvet says:

    Yes, vets get very worried that their clients will lose confidence in them when they admit what they don’t know, but I think your attitude is the more common. Since no one knows everything, pretending complete confidence is never honest. Acknowledging both what we don’t know as individuals and what is not known or understood by the field as a whole is an important part of being honest, with ourselves and our clients.

  4. art malernee dvm says:

    It starts with what is taught at the vet schools and at required by law Continuing Education. If the vets are not taught evidence based medicine there the Ethics of the profession will not improve. The Vet school in florida has a course on how to practice acupuncture. Never seen them offer one on how to practice evidence based medicine.

  5. Evidence-based medicine has drawn attention to important issues in medicine, some of which have hindered its acceptance. For example, some important questions in health care may never be resolved by RCTs for practical reasons. That may occur when adverse events are so infrequent that trials would require impossibly large sample sizes or when health outcomes lie so far in the future that maintaining a trial would be impractical.

  6. art malernee dvm says:

    For example, some important questions in health care may never be resolved by RCTs for practical reasons.>>>>> the old parachute argument you do not need or cannot have a RCT for everything. How silly to say you need a randomized controlled trial to advise people to wear a parachute when they jump out of a plane.

  7. art malernee dvm says:

    below is what I think our founding EBM father would say about taking your dog in for non RCT annual vaccine, annual blood test, annual fecal test annual check up preventative care. Personally I think the most difficult thing about practicing EBVM is how to make money doing it. That includes how to make money freeing the data from RCTs that are now behind paywalls I cannot get to.

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