noun Pathology.

exaggerated allergic reaction to a foreign protein resulting from previous exposure to it.

Origin of anaphylaxis

First recorded in 1905–10; ana- + (pro)phylaxis
Related formsan·a·phy·lac·tic [an-uh-fuh-lak-tik] /ˌæn ə fəˈlæk tɪk/, adjectivean·a·phy·lac·ti·cal·ly, adverban·ti·an·a·phy·lac·tic, adjective, nounpseu·do·an·a·phy·lac·tic, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for anaphylactic

Historical Examples of anaphylactic

  • The histone was so toxic that its anaphylactic properties could not be studied.

  • Idiosyncrasy to cow's milk which is observed sometimes in infants is an anaphylactic phenomenon.

    Food Poisoning

    Edwin Oakes Jordan

  • Among the reactions usually classed as anaphylactic are the occasional cases of sensitivity to particular food substances.

    Food Poisoning

    Edwin Oakes Jordan

  • The first case in the line of descent must start with a severe poisoning that lays the foundation of the anaphylactic inheritance.

    The Treatment of Hay Fever

    George Frederick Laidlaw

  • Now all these specific reactions, the precipitin reaction as well as the anaphylactic reaction, can be called forth by proteins.

British Dictionary definitions for anaphylactic



extreme sensitivity to an injected antigen, esp a protein, following a previous injection
Derived Formsanaphylactic or anaphylactoid, adjectiveanaphylactically, adverb

Word Origin for anaphylaxis

C20: from ana- + (pro) phylaxis
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for anaphylactic

1905, with -ic + medical Latin noun anaphylaxis "exaggerated susceptibility," from French anaphylaxie (1902), from Greek ana- (see ana-) + phylaxis "watching, guarding" (cf. prophylactic). Anaphylactic shock is attested by 1916.


Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for anaphylactic



n. pl. an•a•phy•lax•es (-lăksēz)

Hypersensitivity induced by preliminary exposure to a substance and usually producing a contraction of smooth muscle and a dilation of blood vessels.
anaphylactic shock
Related formsan′a•phy•lactic (-lăktĭk) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for anaphylactic



See anaphylactic shock.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.