Word.ws English Dictionary

herx

herx verb: to experience a Jarisch-Herxheimer reaction, a negative reaction to antibiotic treatment.

Verb

herx (third-person singular simple present herxes, present participle herxing, simple past and past participle herxed)

  1. (informal) To experience a Jarisch-Herxheimer reaction, a negative reaction to antibiotic treatment.
    • These usually last for several hours, and require little more than aspirin and bed rest. Yet many Lyme newsgroup participants write about a "herx" beginning days or weeks after the start of antibiotic therapy, and "herxing" for weeks at a time -- often in a cyclic fashion.2017 October 1, Edward McSweegan, “Lyme Disease: Questionable Diagnosis and Treatment”, in ActionLyme.org, archived from the original on 03 Apr 2023
    • When using any antimicrobial against any Lyme-like infection, most patients will herx at some stage.2020, John Coleman, Rethinking Parkinson’s Disease, page 215

Noun (1)

herx (plural herxes)

  1. (informal) A Jarisch-Herxheimer reaction.
    • For quotations using this term, see Citations:herx.

Noun (2) capitalized: Herx

Herx (plural Herxes)

  1. (alternative) Alternative form of herx (“Jarisch–Herxheimer reaction”).

Forms of herx

Verb
third-person singular presentherxes
present participleherxing
past participleherxed
pastherxed
alternative formHerx
Noun
pluralherxes
pluralHerxes

Origin of herx

Shortened from Jarisch-Herxheimer reaction, which in turn derives from the names of Adolf Jarisch and Karl Herxheimer, physicians who separately described the reaction in syphilis patients.

Questions about herx

What does herx mean?
Herx means to experience a Jarisch-Herxheimer reaction, a negative reaction to antibiotic treatment.
What part of speech is herx?
Herx can be a verb or a noun.
What is the past tense of herx?
The past tense of herx is herxed.

Words near herx in the dictionary

  1. HERVs
  2. Herward
  3. Herwarth
  4. Herwig
  5. Herwigs
  6. herx
  7. herxed
  8. herxes
  9. herxing
  10. herycano
  11. herye

Source and license

Adapted from Wiktionary: herx (page history and authors); Herx (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Cite this entry: “herx.” Word.ws, https://word.ws/herx. Based on Wiktionary, CC BY-SA 4.0.