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

That compares with an average weight loss of 2.3% for people who received a placebo. —Annika Kim Constantino, CNBC, 24 Mar. 2025

One small study was conducted in humans with obesity who received ACV for 12 weeks and followed a low-calorie diet compared to a group taking a placebo (inactive treatment given to people in a study control group). —Sohaib Imtiaz, Verywell Health, 24 Mar. 2025

The groundbreaking trial, published in JAMA Psychiatry, found that participants taking semaglutide consumed less alcohol over two months compared to those on placebo. —Francisco Velasquez, Quartz, 13 Feb. 2025

In fact, the placebo group displayed marginally greater symptomatic improvements, although that difference was considered statistically insignificant. —New Atlas, 3 Apr. 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)