Studies have shown the efficacy of placebos in clinical practice, but the ethical issues are less well defined. To answer the question: is the placebo effect ethical, we evaluate the placebo effect alongside the four ethical principles of medicine:

  1. Autonomy
  2. Beneficence
  3. Non-maleficience
  4. Justice


Autonomy refers to an individuals ability to make decisions about themselves and their own health. In medical ethics, patients are generally only granted true autonomy when they have capacity. Having capacity, means that patients understand and can retain information in order to make a reasoned decision about their health. Autonomy comes hand in hand with informed consent. For a long time, autonomy was the biggest obstacle to the use of the placebo effect in clinical practice.

So, is it possible to have the placebo effect without deception?

For many years, it was thought that deceit was necessary to induce the placebo effect. However, placebo researcher, Ted Kaptchuk, decided to question the conventional wisdom and to run a trial to explore the effects of honestly-prescribed placebos. The results were literally groundbreaking! For the first time, someone had proven that placebos could be prescribed openly and they would still work, with participants receiving an average 60% symptom improvement! When the obstacle of deception is removed, the issue of informed consent is also overcome. These open-label placebos, allow the patient to retain their autonomy, whilst also offering a opportunity for clinical use.


Fundamentally, beneficence is about ‘doing good’. If you are working to promote the welfare of an individual, you are acting with beneficence. So how does the placebo effect relate to beneficence?

When does the placebo effect occur?

To understand the benefits of the placebo effect, we need to know when the placebo effect can be used and the outcome of using the placebo effect in that context. The placebo effect is most effective for conditions that have a psychological component or for conditions that are mediated by the brain i.e. Parkinson’s disease. Having said this, evidence does suggest that the placebo effect is present in a wide range of conditions and that it can interact with the immune system. The remit of the placebo effect is large, but to act with the greatest beneficence, we must focus on those conditions which are most susceptible to the placebo effect i.e. pain, IBS, psychological conditions, Parkinson’s disease etc.

How strong is the placebo effect?

Arguably, there would be little point in trying to use placebos, if they only had a tiny effect. The strength of placebo response can vary hugely between different conditions, but there is also variation at the individual level. We need more research before we can identify all the factors that affect placebo response. In the meantime, we can accept that this variability does mean that for some, the placebo effect can do a lot of good.

How long does the placebo effect last?

Similarly to the last question, the length of the placebo effect can vary. Certain types of placebo can have longer or more potent effects than others. When a placebo relies on the expectations of the patient, the results can be greatly variable. However, the conditioned placebo response is much more predictable. A study of patients with Parkinson’s disease demonstrated that if they were given an injection of an active drug for four days, they would respond to a placebo injection as if it was the drug for two further days. Arguably, if a placebo was only able to offer transient relief, it could be argued that it would be more beneficent to not give the placebo, as the long term results could be very disappointing to the patient. However, as we generally don’t know the potential duration of the placebo effect, the beneficence of placebos will be hard to identify.

Can the placebo effect cure disease?

As far as we know, placebos cannot cure disease. However, they can be highly effective at alleviating symptoms or side effects of other treatments. So, whilst, placebos are not a cure, they can still be used beneficently for symptom relief.


The evil step-sister of beneficence is maleficence (doing harm). Therefore, non-maleficence can be easily understood as ‘do no harm’. In the ethics of placebos, non-maleficence is a pivotal factor.

When should placebos be used?

It is vital that patients do not forgo effective treatment in order to take placebos. Therefore, placebos should only be considered in the following situations:

  • If there is no effective conventional treatment available
  • If placebos are to be used alongside conventional treatment
  • If the condition is not severe enough to warrant conventional medical intervention

A doctor should use their knowledge and judgement when making a decision about the suitability of placebos for a patient and how placebos should be used. For example, a placebo should not be used as a cancer treatment, as placebos are not effective in cancer and alternatives are available. However, placebos may be used to help alleviate side effects of cancer treatments which could have a brain-mediated component such as nausea, pain or fatigue.

What is the nocebo effect?

No discussion of non-maleficence and placebos would be complete without mention of the nocebo effect. The nocebo effect is the negative version of the placebo effect. Instead of doing good, it can do harm. It is generally assumed that no clinician would willingly harm a patient via the nocebo effect, but it should be considered that a negative interaction between the doctor and patient could contribute to the nocebo effect. Therefore, doctors should be cognisant of how they communicate with patients, to ensure they do not inadvertently reduce the effectiveness of a treatment via the nocebo effect.


In medical ethics, justice refers to three key factors:

  • Compliance to law
  • Respect for human rights
  • Fair and justified allocation of resources

Is it legal to prescribe placebos?

In most countries, it is not illegal to prescribe placebos. However, as we’ve discussed, it could be unethical. If a doctor was to harm a patient by prescribing a placebo instead of an effective conventional treatment, they may be subject to legal action and a charge of medical negligence.

What about placebos and human rights and fair allocation of resources?

The UN’s list of human rights only includes one that is applicable to healthcare: Social Security: We all have the right to affordable housing, medicine, education, and childcare, enough money to live on and medical help if we are ill or old. 

With this in mind, placebos could help to support human rights in various ways. For example, as placebos do not have any active ingredients, they should be more affordable than standard medication. This could enable treatment to be provided to individuals who may not be able to afford conventional treatment.

Evidently, it is not ethical that poorer individuals should not have access to conventional treatment, however, that is the unfortunate reality for millions of people. Perhaps a placebo is better than nothing. Furthermore, studies have shown that the conditioned placebo effect can help to reduce the amount of some medications required by 1/3, which could also help to spread resources across more people and to make treatment more affordable without reducing efficacy.


So, is the placebo effect ethical? After analysing the placebo effect against the four principles of medical ethics, it can be concluded that there is nothing inherently unethical about the placebo effect. It all depends upon how it is used. Placebos can be used ethically and beneficently, whilst supporting the patients autonomy. In addition, on a global scale, placebos have the potential to help address health inequalities and to improve social justice in global health.

If you’ve enjoyed reading ‘Is the placebo effect ethical?’ you may find our article on the guidelines for prescribing placebos of interest.

If you have anything to add, please share your thoughts in the comments.

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