placebo effect

American  

[pluh-see-boh] / pləˈsi boʊ /

noun

1. a reaction to a placebo manifested by a lessening of symptoms or the production of anticipated side effects.

---

placebo effect British  

noun

1. med a positive therapeutic effect claimed by a patient after receiving a placebo believed by him to be an active drug See control group

---

Etymology

Origin of placebo effect

First recorded in 1945–50

Example Sentences

See Examples For:

placebo effect

"You can shape a treatment to fit the belief system without explicitly endorsing it," French said, conceding an exorcism might even have a beneficial placebo effect in some cases.

From Barron's ● Jul. 19, 2026

The other half received a sham treatment designed to control for the placebo effect.

From Science Daily ● May 22, 2026

GP Ben Davis also warns that TRT can have a placebo effect, leaving patients sometimes taking and paying for medication privately, that they do not need.

From BBC ● Feb. 14, 2026

The placebo effect might also be at work.

From The Wall Street Journal ● Dec. 29, 2025

As it happens, Denis Papin, who had qualified as a doctor, was the first to describe the placebo and the placebo effect, in a letter to Leibniz, 11 or 12 August 1704.

From "The Invention of Science" by David Wootton