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.

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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

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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.

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placebo Cultural  

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

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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

Blood pressure improved in the peppermint oil group, while the placebo group showed no meaningful change.

From Science Daily ● Aug. 22, 2026

A third study followed approximately 600 of the original 1,000 participants who had been assigned either digoxin or placebo.

From Science Daily ● Aug. 16, 2026

Half received a low dose of digoxin in addition to their usual treatment for an average of three years, while the other half received a placebo.

From Science Daily ● Aug. 16, 2026

Patients who took Orzeyful showed improvements in staying awake, had fewer instances in which they lost muscle control and slept better at night than those on placebo.

From The Wall Street Journal ● Aug. 6, 2026

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

From "The Science of Breakable Things" by Tae Keller

According to the researchers, this makes open-label placebos a promising and ethically acceptable strategy for supporting healthy aging.

From Science Daily ● Jun. 25, 2026

The U-turns mark a broader retreat from demands, pushed under former FDA vaccines and biotech drugs division leader Vinay Prasad, that rare-disease drugmakers test their experimental medicines against placebos to make sure the drugs work.

From The Wall Street Journal ● Jun. 22, 2026

It was seen as not only socially acceptable but humane to prescribe placebos.

From Slate ● Jan. 30, 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

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