placebo

noun

pla·​ce·​bo plə-ˈsē-(ˌ)bō 

plural placebos

1

a

: 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

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 another study, people with migraines who used a handheld VNS device (gammaCore) on the side of their neck were significantly more likely to be pain-free within 30 minutes to an hour of VNS, compared to those receiving a sham (placebo) treatment. —Clarissa Brincat, Popular Science, 25 Sep. 2025

Using modeling data from one small study, the researchers estimated that rapamycin users reduced their biological age by around four years, compared to a slight increase in the placebo group. —New Atlas, 24 Sep. 2025

Five years later, Frye confirmed those findings in a study that compared children receiving leucovorin to a group getting a placebo drug. —Alice Park, Time, 23 Sep. 2025

Leucovorin is prescribed for chemotherapy patients and for anemia, but a study out of India in November found that children with autism did better on the medicine than the placebo group. —Marina Johnson, Louisville Courier Journal, 23 Sep. 2025

Word History

Etymology

Latin, I shall please

First Known Use

1785, in the meaning defined at sense 1a

Phrases Containing placebo

• placebo effect

Kids Definition

placebo

noun

pla·​ce·​bo plə-ˈsē-bō 

plural placebos

1

: a medicine that usually has no effect on a disease and is prescribed by a doctor for the mental relief it offers a patient

2

something that is meant to soothe

Etymology

from Latin placebo "I shall please"

Medical Definition

placebo

noun

pla·​ce·​bo plə-ˈsē-(ˌ)bō 

plural placebos

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)