Herx Reactions

Functional medicine often has answers for patients who haven’t found solutions elsewhere, and it’s so exciting to understand your symptoms finally and have a path forward for healing. But the path to healing isn’t always straightforward.

Have you ever started a new protocol, only to feel worse as you begin? You may be experiencing a herx reaction, and we’re here to tell you that it’s not a sign to give up. Instead, it’s a sign to keep going. We’ll explain herxing and what to expect in today’s article, including:

What is herxing? Or what is a Herx reaction? Herx symptoms How to manage herxing symptoms Herx reactions vs. allergic reactions Timing and duration of Herx detox

What is HERX/Healing Crisis/Response?

The Jarisch Herxheimer reaction is named for two dermatologists: Adolf Jarisch and Karl Herxheimer. It was first described in the 1800s when Jarisch observed a clinical response to syphilis treatment (antibiotics) in some patients. Herxheimer independently reported the same clinical findings in the early 1900s.

Known as the Jarisch-Herxheimer reaction, or Herx for short, this response is a transient inflammatory immune response . It originally described the die-off reaction some people experience when beginning antibiotics. As the antibiotics rapidly kill the bacterial infection, the bacteria release toxins. When the system can’t detoxify and eliminate the toxins quickly enough, symptoms occur.

Herx has come to describe other cases of transient symptoms that occur after beginning a new medication or protocol. It’s not just common in those receiving antibiotics (Lyme Herx is common in Lyme disease, for example). Herx symptoms or “a healing crisis” may occur when beginning a gut protocol , even with herbs and supplements instead of pharmaceuticals.

Herx symptoms or “a healing crisis” may occur when beginning a gut protocol , even with herbs and supplements instead of pharmaceuticals.

In our practice, we also observe this type of reaction during the first days of an elimination diet protocol. We educate our patients that it’s likely they will feel worse before they feel better.

HERX Symptoms and Why They Occur

The Herx effect may involve several flu-like symptoms and range from mild discomfort to severe Herx symptoms in some individuals.

Herx reaction symptoms may include :

Fever Chills Digestive symptoms Headaches Rapid heartbeat Low blood pressure Flushing Fatigue Brain fog Rashes and breakouts Mood changes Hunger and cravings

Symptoms may occur because of pathogen die-off, as discussed. Other reasons include blood sugar recalibration, withdrawal from inflammatory or addictive foods, and the energy requirements of detoxification itself.

Support: How to Manage and Alleviate Discomfort

In the functional medicine setting, our goal is to support the body’s detoxification systems and provide comfort measures for symptoms. In the early days of a new protocol, as your body detoxifies and adjusts, you may need more self-care and compassion. This might mean clearing your schedule, so you have more time to tend to your needs.

Gentle support may include:

More rest Gentle movement Increasing filtered water and nourishing broths Easy-to-digest organic food , especially foods that support detoxification, such as cruciferous veggies, colorful fiber-rich plant foods, and protein Hot baths, sauna, dry skin brushing, and other detoxification support Meditation and mindfulness

In some cases, it may make sense to ease into your functional medicine protocol more gradually to minimize symptoms. Please talk with your provider about any new symptoms that arise when beginning a new medication, supplement, or health protocol.

Is it a Herx Reaction or a True Allergic Reaction?

A true allergic reaction, anaphylaxis, is life-threatening and requires immediate medical attention. Symptoms may include:

Swelling of the tongue and lips Constricted breathing Hives Stuffy nose, sneezing, watery eyes

It is possible to have an allergic reaction to a new medication. However, an allergic response is different than Jarish Herxheimer, which is not life-threatening.

Timing and Duration: How Long Herx Lasts

As Jarisch Herxheimer reactions were originally described in response to the effects of antibiotic treatment, symptoms tended to come on quickly and also resolve quickly, in about 24 hours.

Clinically, in our functional medicine practice, we see patients begin a new gut protocol or elimination diet that may feel worse before better. In these cases, symptoms are typically mild and last for several days or a week. In some cases, they may last up to 10 days. However, once symptoms pass, patients report a notable improvement in energy, clarity, and well-being.

The message is that Herx symptoms don’t mean the protocol or elimination diet isn’t working; in fact, some discomfort is a positive sign that the body is responding. That’s why we often call this a healing response; you are beginning to heal.

The message is that Herx symptoms don’t mean the protocol or elimination diet isn’t working; in fact, some discomfort is a positive sign that the body is responding.

Of course, we never want you to feel alone in your healing. The Fork is here to support you. We always discuss what you can expect when embarking on a new healing path and are here to help you troubleshoot along the way. If you’re ready to experience a new kind of medicine, one personalized for you, please reach out today !

References

Wood, J. M., & Sbar, E. (2025). Jarisch-Herxheimer Reaction . In StatPearls . StatPearls Publishing. Gautam, M., Sethi, S., & Nadkarni, N. J. (2023). Jarisch‒Herxheimer reaction . Indian journal of sexually transmitted diseases and AIDS , 44 (1), 79–81.