nocebo effect
noun
: the development of adverse side effects or worsening in the condition of a patient that occurs in response to medical treatment but cannot be considered due to the specific treatment used
With a nocebo effect, if test subjects believe there may be side effects, they often experience them. Again, expectations shape reality.—
Sanjay Gupta
Sanjay GuptaExamples of nocebo effect in a Sentence
Recent Examples on the Web
That’s the nocebo effect—the evil twin of the placebo.
—David Meade, Forbes.com, 18 July 2025
Encouraging a more thoughtful and grounded relationship with health information online could be a key step in mitigating the impact of the nocebo effect.
—Peter Suciu, Forbes.com, 27 Mar. 2025
The data clearly indicated that a nocebo effect was occurring – in other words, participants were experiencing an entirely psychological phenomenon in which a harmless substance causes a harmful effect.
—Elsbeth Sites, Discover Magazine, 3 June 2014
The relevance of the nocebo effect is not limited to clinical trials.
—Guest Blogger, Discover Magazine, 24 July 2012
Or a nocebo effect when expectations make people feel worse rather than better.
—Neuroskeptic, Discover Magazine, 8 Sep. 2010
The placebo effect also has a shadowy twin: the nocebo effect.
—Carl Engelking, Discover Magazine, 5 Oct. 2017
The nocebo effect is another important aspect of mindset.
—Jennifer C. Lovejoy, Scientific American, 7 Dec. 2022
Marino, who watched the video, told the San Diego Union-Tribune a nocebo effect could explain Faiivae's reaction since his symptoms did not suggest an overdose.
—Miriam Fauzia, USA TODAY, 25 Aug. 2021
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David Meade, Forbes.com, 18 July 2025
Encouraging a more thoughtful and grounded relationship with health information online could be a key step in mitigating the impact of the nocebo effect.
—Peter Suciu, Forbes.com, 27 Mar. 2025
The data clearly indicated that a nocebo effect was occurring – in other words, participants were experiencing an entirely psychological phenomenon in which a harmless substance causes a harmful effect.
—Elsbeth Sites, Discover Magazine, 3 June 2014
The relevance of the nocebo effect is not limited to clinical trials.
—Guest Blogger, Discover Magazine, 24 July 2012
Or a nocebo effect when expectations make people feel worse rather than better.
—Neuroskeptic, Discover Magazine, 8 Sep. 2010
The placebo effect also has a shadowy twin: the nocebo effect.
—Carl Engelking, Discover Magazine, 5 Oct. 2017
The nocebo effect is another important aspect of mindset.
—Jennifer C. Lovejoy, Scientific American, 7 Dec. 2022
Marino, who watched the video, told the San Diego Union-Tribune a nocebo effect could explain Faiivae's reaction since his symptoms did not suggest an overdose.
—Miriam Fauzia, USA TODAY, 25 Aug. 2021
Cite this Entry
“Nocebo effect.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nocebo%20effect. Accessed 13 Aug. 2025.
Copy CitationMedical Definition
nocebo effect
noun
: the development of adverse side effects or worsening in the condition of a patient that occurs in response to medical treatment but cannot be considered due to the specific treatment used
With a nocebo effect, if test subjects believe there may be side effects, they often experience them. Again, expectations shape reality.—Sanjay Gupta, Chasing Life: New Discoveries In The Search For Immortality …
Sanjay Gupta, Chasing Life: New Discoveries In The Search For Immortality …The placebo effect has an evil twin: the nocebo effect, in which dummy pills and negative expectations can produce harmful effects.—Helen Pilcher, New Scientist
Helen Pilcher, New ScientistLove words? Need even more definitions?
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