Meanings
herx1
present singular third person herxes · participle present herxing · participle past herxed · past herxed · alternative Herx
- informalmedicineTo experience a Jarisch-Herxheimer reaction, a negative reaction to antibiotic treatment.
When using any antimicrobial against any Lyme-like infection, most patients will herx at some stage.
2020, John Coleman, Rethinking Parkinson’s Disease, page 2152 more examples
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 2023Has anyone else herxed intensely even on low dose fenben? I started with 150mg and herxed, backed down to 70mg and still herxed along with my 100mg doxy.
2021 March 4, Fredsmith, “herxing like crazy on Fenben”, in HealingWell
Herx2
Origin
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.
Full word history & related roots →Cite this entry
herx. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/herx
“herx.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/herx. Accessed November 3, 2026.
WatkinsX Dictionary, s.v. “herx,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/herx.
Source: herx on Wiktionary, CC BY-SA 4.0.