placebo

American  

[pluh-see-boh, plah-chey-boh] / pləˈsi boʊ, plɑˈtʃeɪ boʊ /

noun

placebos, plural placeboes plural

1. Medicine/Medical, Pharmacology.

   1. a substance having no pharmacological effect but given merely to satisfy a patient who supposes it to be a medicine.

   2. a substance having no pharmacological effect but administered as a control in testing experimentally or clinically the efficacy of a biologically active preparation.

2. Roman Catholic Church. the vespers of the office for the dead: so called from the initial word of the first antiphon, taken from Psalm 114:9 of the Vulgate.

---

placebo British  

/ pləˈsiːbəʊ /

noun

1. med an inactive substance or other sham form of therapy administered to a patient usually to compare its effects with those of a real drug or treatment, but sometimes for the psychological benefit to the patient through his believing he is receiving treatment See also control group placebo effect

2. something said or done to please or humour another

3. RC Church a traditional name for the vespers of the office for the dead

---

placebo Scientific  

/ plə-sē′bō /

1. A substance containing no medication and prescribed to reinforce a patient's expectation of getting well or used as a control in a clinical research trial to determine the effectiveness of a potential new drug.

---

placebo Cultural  

1. A substance containing no active drug, administered to a patient participating in a medical experiment as a control.

---

Discover More

Those receiving a placebo often get better, a phenomenon known as the placebo effect.

Other Word Forms

Noun Inflected Forms

• placeboes
  plural
• placebos
  plural

Etymology

Origin of placebo

1175–1225 placebo for def. 2; 1775–85 placebo for def. 1; Middle English < Latin placēbō “I shall be pleasing, acceptable”

Explanation

A patient's symptoms sometimes disappear just because they believe that they are being treated. Even when doctors give them a biologically inactive drug, otherwise known as a placebo, the patients swear they are cured. In clinical drug-trials, to rule out what is called the placebo effect, scientists give half of the trial participants a placebo. If a government replaces food stamps with a coloring book give-away, it might be dismissed by child advocates as nothing more than a placebo. Placēbō is Latin for "I'll please (you)," in other words, I'll keep you happy, even though I'm just giving you a placebo.

Example Sentences

See Examples For:

placebo placebos

The French drugmaker said Friday that Bylvay missed the study’s primary objective of showing an improvement in native liver survival rates compared to placebo.

From The Wall Street Journal ● Jul. 24, 2026

"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

Lambers Heerspink said, "In the finerenone group, 13.9 percent experienced such a complication, compared to 16.9 percent in the placebo group. That amounts to a reduction in risk of approximately 23 percent."

From Science Daily ● Jul. 16, 2026

However, it failed to meet the primary efficacy endpoint compared with placebo when treating transthyretin amyloid cardiomyopathy.

From The Wall Street Journal ● Jul. 9, 2026

Twig gladly abandoned her original question—something with food coloring and placebo effects.

From "The Science of Breakable Things" by Tae Keller

The findings suggest that placebo treatments can improve several aspects of functioning in older adults, with open-label placebos performing as well as, or in some cases better than, deceptive placebos.

From Science Daily ● Jun. 25, 2026

He also appreciated the role of psychology, placebos and positive thinking.

From The Wall Street Journal ● Apr. 14, 2026

While studies showed that Sarepta’s Amondys 45 and Vyondys 53 treatments for Duchenne muscular dystrophy worked better than placebos, the company said the results did not reach statistical significance.

From MarketWatch ● Nov. 3, 2025

But none has undergone the large, randomized human trials comparing them with placebos that would be needed for FDA approval to enter the market.

From Science Magazine ● Mar. 31, 2024

If placebo effects were this good, they should just make placebos the way to treat depression—maybe that’s what they did; maybe Zoloft was cornstarch.

From "It’s Kind of a Funny Story" by Ned Vizzini