Intended for healthcare professionals


Open label placebo: can honestly prescribed placebos evoke meaningful therapeutic benefits?

BMJ 2018; 363 doi: (Published 02 October 2018) Cite this as: BMJ 2018;363:k3889
  1. Ted J Kaptchuk, professor of medicine1,
  2. Franklin G Miller, professor of medical ethics2
  1. 1Program in Placebo Studies, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
  2. 2Weill Cornell Medical College, New York, NY USA
  1. Correspondence to: T J Kaptchuk ted_kaptchuk{at}

Results from small clinical trials suggesting that placebos can be ethically and effectively used in clinical practice warrant further study, argue Ted Kaptchuk and Franklin Miller

Placebo treatments in randomised controlled trials produce significant improvement in many subjective symptoms.1 Until recently, it has been presumed that placebo pills can produce therapeutic benefit only if patients do not know that they have received a placebo. Intriguingly, the results of several, albeit small, randomised trials of open label placebo suggest that patients can experience symptom relief from taking pills that they know lack any medication.

The placebo concept

For biomedicine, if an intervention is equivalent to placebo treatment it warrants rejection. In the past 20 years, basic science research has shown that although placebo treatments primarily modify subjective symptoms, various neurotransmitters (eg, endorphins, dopamine, and cannabinoids) and specific, quantifiable, and relevant regions of the brain are engaged.2 Potential genetic markers are emerging.3 Importantly, clinical research has shown that placebo effects are more than spontaneous improvement and regression to the mean.4 Placebo effects have gained a new legitimacy.

This raises a critical question: can placebo pills be used ethically in clinical practice? Conventional wisdom has assumed that deception or concealment is necessary for placebos to work. Until recently, this belief has posed an insurmountable barrier to ethically harnessing placebo effects.

Open label placebo studies

One of us (TK) has been an investigator in four randomised trials of open label placebo, each in different conditions, each with over 60 patients. In these four studies patients were randomised to receive open label placebo (pills described as “inert placebos containing no medication”) plus usual treatment or usual treatment (and in one case no treatment.)

To control for provider interaction and time, patients in three of the studies received information about both groups, had identical patient-provider interactions, and were assigned …

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