Herxheimer Reactions

What is a Herxheimer reaction (herx)?

Dr. Adolph Jarisch and Dr. Karl Herxheimer first discovered this reaction in syphilis patients.

A Jarisch-Herxheimer reaction is...

  • Common when Lyme patients begin antibiotics.
  • Often called a “Herx.”
  • A temporary worsening of symptoms.
  • Caused by dying bacteria.
  • Can last several days or longer.

Symptoms can include:

Severe headache
Profound fatigue
Suicidal thoughts
Increased pain
Heart problems
Exacerbation of  previous symptoms
New symptoms


If symptoms are severe or life-threatening, doctors  may stop treatment and resume it later.

Doctors may resume treatment with a lower dose and gradually increase it.

Supplements and vitamins can boost the immune  system and also cause a Herx.

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