nocebo

noun

no·ce·bo ˌnō-ˈsē-(ˌ)bō

plural nocebos

: a harmless substance or treatment that when taken by or administered to a patient is associated with harmful side effects or worsening of symptoms due to negative expectations or the psychological condition of the patient

Did you know?

Nocent has been in the English language as a word for "harmful" since the 15th century. It comes from Latin nocēre, meaning "to harm." Latin nocebo is a close relative that means "I will be harmful" and that contrasts with placebo, meaning "I shall please." People in medicine began using "placebo" for inert preparations prescribed solely for a patient's mental relief, and not for relieving a disorder, in the late 18th century. As doctors began to observe the effects of placebos, some noticed that the harmless preparations actually sometimes caused detrimental effects on the patient's health. English speakers began using the word nocebo for substances causing such adverse reactions in patients in 1961.

Examples of nocebo in a Sentence

Recent Examples on the Web Overall, the nocebo responses clearly seem to be skewing our experience with COVID-19 vaccines, which are being used the world over. —

Beth Mole, Ars Technica, 19 Jan. 2022 Expectations are key to both placebo and nocebo. —

Elizabeth Preston, Discover Magazine, 9 July 2014 Chemically, nocebo seems to use the same toolkit that placebo does. —

Elizabeth Preston, Discover Magazine, 17 July 2012 Led by Winfried Häuser of the Technical University of Munich, the authors say that nocebo in the doctor's office can add unnecessary pain and distress to ordinary procedures. —

Elizabeth Preston, Discover Magazine, 17 July 2012 For the first time, the role of verbal suggestion and conditioning in placebo and nocebo effects on itch was experimentally investigated. —

Seriously Science, Discover Magazine, 25 Mar. 2014 As such, the researchers argue that highlighting the potential for nocebo responses could reduce side effects and help improve vaccine uptake. —

Beth Mole, Ars Technica, 19 Jan. 2022 Hudson says there may be a placebo effect available to marathoners who believe strongly in the benefits of a training volume reduction, but the current narrative seems more likely to produce the opposite effect on performance, a nocebo. —

Leo Spall, Outside Online, 11 Oct. 2019 Whereas a placebo is an inert substance that exerts a beneficial effect, a nocebo is an inert substance that exerts an unpleasant effect. —

Richard Klasco, New York Times, 1 June 2018 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'nocebo.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

borrowed from Latin nocēbō "I will harm" (1st person person singular of nocēre "to damage, harm"), on the model of placebo — more at noxious

First Known Use

1961, in the meaning defined above

Time Traveler

The first known use of nocebo was in 1961

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Cite this Entry

Style

“Nocebo.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nocebo. Accessed 3 Dec. 2023.

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Medical Definition

nocebo

noun

no·ce·bo ˌnō-ˈsē-(ˌ)bō

: a harmless substance or treatment that when taken by or administered to a patient is associated with undesirable or harmful side effects or worsening of symptoms due to negative expectations or the psychological condition of the patient