from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A substance that causes undesirable side effects as a result of a patient's perception that it is harmful rather than as a result of a causative ingredient.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun pharmacology A substance which a patient experiences as harmful due to previous negative perception, but which is in fact pharmacologically (medicinally) inactive.


from The American Heritage® Dictionary of the English Language, 4th Edition

[Latin nocēbō, I will harm, first person sing. future tense of nocēre, to harm (on the model of placebo); see nek- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin nocēbō ("I will harm"), first-person singular future active indicative of noceō ("I harm"), by analogy with placebo.


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  • A substance producing harmful effects in someone because it is believed to be harmful, but which in reality is harmless (the opposite of placebo). From A.Word.A.Day, 3/4/08.

    March 4, 2008

  • Like tobacco, right?

    Just kidding.

    March 5, 2008

  • Ah, but that would depend on whom you are asking. ;-)

    March 5, 2008

  • Coined on the model of placebo from the Latin nocēre, "to hurt", (related to, for example, noxious and obnoxious).

    “Cannon’s analysis of ‘Voodoo Death’ allows us to think the affect of bioterrorism in terms of what we could call ‘nocebos’, the dark twin of a ‘placebo’ … the fear which issues from the negative statement, or hex, attains a reality more powerful than the actual threat. In contemporary medicine, there is much made of the increased likelihood of succumbing to illness if verbal suggestions of susceptibility are emphasized…�?

    Luciana Parisi & Steve Goodman, The Affect of Nanoterror

    March 19, 2009

  • "...the nocebo phenomenon wherein a patient produces the symptoms of a misdiagnosed disease, even to the degree of dying on the day that the doctor gave as the expected time to live, although the particular disease was not present."

    The Abundance Matrix, p. 5

    August 3, 2009

  • This is too freaky.

    August 4, 2009

  • no-ti-cebo bene (mal) or is that nota bene? Well?

    August 4, 2009