Watch any commercial about prescription drugs, and you’ll hear a list of the potential side effects. Some side effects are mild, and some are a little more severe, but all medications sold in the U.S. must pass stringent tests for safety. In this article, we’ll discuss the Jarisch-Herxheimer reaction, which occurs within 1–2 hours for up to 90% of patients after treating a spirochetal infection with antibiotics.

The Jarisch-Herxheimer reaction, also known as Herxheimer reaction, is characterized by symptoms such as fevers, chills, myalgia, headaches, and body aches. The Jarisch-Herxheimer reaction can cause flu-like symptoms, which can last for 24 hours to a few days. This reaction is commonly seen after treatment of infections caused by spirochetes, such as Lyme disease and syphilis.


Herxheimer Reaction - What It Is and What Can I Do About It?

What Causes the Herxheimer Reaction?

After receiving antibiotics for spirochetal illnesses, some patients may experience the Jarisch-Herxheimer reaction. The reaction is caused by the release of toxins from the bacteria as they are being killed by the antibiotics. The body may respond with an immune response, leading to inflammation.

The Herxheimer Reaction — Feeling worse before Feeling Better

Herxheimer reactions can cause temporary symptoms that may be like the flu, such as body aches, muscle discomfort, a sore throat, sweating, tiredness, chills, and nausea. These symptoms may occur as the body reacts to the release of toxins from bacteria being killed by antibiotics. Worsening symptoms during treatment may not necessarily indicate that the therapy is ineffective, but rather that the medication is effectively killing the infection and causing a temporary increase in the release of toxins.

Common symptoms of a Herxheimer reaction include:

  • Headaches
  • Muscle and joint pain
  • Fatigue
  • Chills
  • Fever
  • Nausea and vomiting
  • Skin rash or itching
  • Changes in mood, such as anxiety or depression

It is important to note that the above symptoms are not unique to the Herxheimer reaction and can also be caused by other factors. Additionally, not all individuals with infections will experience a Herxheimer reaction. It is important to consult a healthcare professional for proper diagnosis and treatment.

Herxheimer Reaction Time Frames

The onset and duration of Herxheimer reactions can vary and are dependent on individual factors. If symptoms persist or worsen, it is recommended to contact a medical provider. To manage symptoms during a Herxheimer reaction, it is advised to hydrate and get plenty of rest.

Final Thoughts about Herxheimer Reactions

What we experience as pain is inflammation leaving the body. In most cases, you will feel better within a few days. It is important to consult a healthcare professional for proper diagnosis and treatment.


  1. The Jarisch-Herxheimer reaction:
  2. Symptoms of the Herxheimer reaction:
  3. Causes of the Herxheimer reaction:
  4. Time frame of Herxheimer reactions:
  5. Colloidal silver and the Herxheimer reaction:

Find more information on the Herxheimer reaction in the following scientific journals:

  1. Clinical Microbiology Reviews
  2. The American Journal of Medicine
  3. The Journal of Infectious Diseases
  4. The Journal of Clinical Psychopharmacology
  5. Current Infectious Disease Reports.