pla·​ce·​bo | \ plə-ˈsē-(ˌ)bō \
plural placebos

Definition of placebo 

1a : a usually pharmacologically inert preparation prescribed more for the mental relief of the patient than for its actual effect on a disorder
b : an inert or innocuous substance used especially in controlled experiments testing the efficacy of another substance (such as a drug)
2 : something tending to soothe

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Did You Know?

Doctors doing research on new treatments for disease often give one group a placebo while a second group takes the new medication. Since those in the placebo group usually believe they're getting the real thing, their own hopeful attitude may bring about improvement in their condition. Thus, for the real drug to be considered effective, it must produce even better results than the placebo. Placebos have another use as well. A doctor who suspects that a patient's physical symptoms are psychologically produced may prescribe a placebo in the hope that mentally produced symptoms can also be mentally cured.

Examples of placebo in a Sentence

Recent Examples on the Web

In the trials, women who took the drug had greater decreases in bone loss than did those who received placebo, and this wasn’t entirely surprising. Julia Belluz, Vox, "Women with endometriosis suffer terrible pain. There’s finally a new treatment option.," 24 July 2018 View Sample Sign Up Now Even these people, however, did not show much difference in their cognitive testing scores after more than a year on the drug compared to people who received a placebo. Alice Park, Time, "Another Alzheimer’s Drug Has Failed. But Researchers Aren't Giving Up," 24 Jan. 2018 Fourteen of the men took two 600-milligram doses of ibuprofen per day for six weeks — an amount consistent with what many athletes take to manage aches and pains — while the remaining 17 took placebo pills. Jamie Ducharme, Time, "Regular Ibuprofen Use May Contribute to Male Infertility, Study Says," 9 Jan. 2018 This was much lower than the rate in the placebo group—11 percent and 59 percent, respectively—but shows that the treatment and testing came with important risks. Cathleen O'grady, Ars Technica, "Some promising news for kids with peanut allergies," 23 Nov. 2018 The trial also enrolled a smaller number of adults, but the drug didn’t provide a significant benefit versus placebo in these participants. Peter Loftus, WSJ, "Experimental Drug Shows Promise Protecting Against Peanut Allergies," 18 Nov. 2018 For example, many studies only look at participants who self-report using cannabis, which provides much weaker evidence than randomly assigning a group of participants to take either a cannabis product or a placebo. Angela Chen, The Verge, "Government bans on pot research have created room for marijuana health hype," 6 Nov. 2018 Further Reading Homeopathy successfully turns water into a placeboResearchers note that Figure 3 of the paper appeared to include suspiciously identical data points across different experiments. Beth Mole, Ars Technica, "Bogus homeopathy data published in top journal sparks outcry, facepalms," 10 Oct. 2018 They are given experimental drugs or placebo versions of them for several years. Marilynn Marchione, The Seattle Times, "Studies in healthy older people aim to prevent Alzheimer’s," 1 Oct. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'placebo.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of placebo

1785, in the meaning defined at sense 1a

History and Etymology for placebo

Latin, I shall please

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Statistics for placebo

Last Updated

6 Jan 2019

Look-up Popularity

Time Traveler for placebo

The first known use of placebo was in 1785

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More Definitions for placebo



English Language Learners Definition of placebo

medical : a pill or substance that is given to a patient like a drug but that has no physical effect on the patient


pla·​ce·​bo | \ plə-ˈsē-(ˌ)bō \
plural placebos

Medical Definition of placebo 

1 : a usually pharmacologically inert preparation prescribed more for the mental relief of the patient than for its actual effect on a disorder
2 : an inert or innocuous substance used especially in controlled experiments testing the efficacy of another substance (as a drug)

Keep scrolling for more

More from Merriam-Webster on placebo

Spanish Central: Translation of placebo

Nglish: Translation of placebo for Spanish Speakers

Britannica English: Translation of placebo for Arabic Speakers

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marked by shyness and lack of polish

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