• Annie V. Henry

What is Herxing? | The Ins and Outs of the Jarisch-Herxheimer Reaction

Updated: 8 hours ago

If you are new to Lyme disease treatment—be it your run-of-the-mill pharmaceutical antibiotics or if you’ve opted for a more natural and alternative treatment plan—you may at some point wonder: why the heck do I feel worse? Treatment and medicine are supposed to make patients feel better, right? So why is your Lyme treatment making you feel like crap?



It is not uncommon for Lyme disease patients to start feeling significantly worse a few days into taking antibiotics for the first time. It is easy to assume that the medicine isn’t working—that it is causing adverse effects or that maybe you are experiencing an allergic reaction to the medication. A logical response for both patients and doctors would be to stop with that treatment protocol and explore other options. However, I would argue that—contrary to surface-level logic—this would be a mistake.


If this fits your story, don’t be alarmed or discouraged when you react negatively to antibiotics. Most likely, what you are experiencing is not only normal for Lyme patients but is almost invited. You are experiencing what is known as a Jarisch-Herxheimer reaction, or what us Lymies call a “herx”. Some day you may find yourself thinking of herxing as a good thing.


Let me explain…


Herxes Explained—Why Does Herxing Happen?

A herx is your body’s reaction to the die-off of Lyme (or co-infection) bacteria. When bacteria are killed off by antibiotics, they release toxins. Naturally, your body works to remove these toxins from your system. If bacteria are killed off at a faster rate than your body can handle, your system will be left with a backup of dead bacteria and toxins. This accumulation of toxins can cause a negative reaction, which often involves a worsening of symptoms. From headaches, to increased fatigue, to an influx of your usual Lyme symptoms—this die-off reaction can make patients feel miserable. Well, my friends, this unfortunate reaction is a herx.


In other words, herxing is a reaction to your body being ‘over-toxified’. This is why detox is such an important aspect of Lyme disease treatment.


Side note: the term “herxing” is named after dermatologists Adolf Jarisch and Karl Herxheimer. These two scientists discovered the herx reaction upon noticing negative reactions in their patients who were being treated with antibiotics for syphilis. Fascinating, huh? (note the mild sarcasm).


What Does Herxing Feel Like?

I usually notice herxes a few hours after taking antibiotics or after the completion of my Lyme treatment. Sometimes they are mild and tolerable. Sometimes my herxes put me on my ass.


Just like normal Lyme disease symptoms, herxes range in frequency and severity. They can also manifest as different symptoms. From my experience, herxes cause similar symptoms as the active tick-borne infections in my body. I notice that some of my most persistent Lyme symptoms—including headaches, fatigue, joint and muscle pain, and dizziness—are also characteristic of my herxes. Except when I herx, often my symptoms feel significantly more severe. During the worst of my treatment, my herxes were intense. It is astonishing just how bad they can make you feel. Just when you get used to managing your Lyme symptoms—BAM! A herx hits you, reminding you how dreadful Lyme disease can be (as if you forgot, ha!).


Another way I would describe herxing is that it feels like I’m hungover. I feel especially achy and drained of energy. Headaches and brain fog—two symptoms of a bad hangover—often accompany my herxes.


You may even experience new symptoms, so do not be afraid if something random comes up. Brain fog was one I didn’t experience too often until I started my Lyme disease treatment. Then all of a sudden—hello brain fog! I felt like my brain was clouded and I had lost part of my cognitive ability and short-term memory. I may have well thrown out my keys, I lost them so many times.


So if your herx reactions may feel similar to your regular symptoms, how can you tell the difference between a herx and regular symptoms? The key is timing. Herxes often correlate with treatment. I notice herxes an hour or two after I take my medication, and especially a few days into starting a new antibiotic or treatment. It can take some time for your medicine to effectively kill off the bacteria, which causes a lag between treatment and herxes.


Herxing will feel different for everyone—but a good rule of thumb is to trust your gut. If something really doesn’t feel right, consult with your doctor. It is possible that you may be having a serious reaction to your medication that is not a herx. Keep that in mind when evaluating your herxes and make sure to update your doctor as your herxes develop and change.


Tolerating Herxes and Finding a Balance

Herxes are an inevitable part of Lyme treatment. Knowing that you will have to endure extra pain, fatigue, and discomfort while your antibiotics go to work is an unpleasant reality to accept. Eventually, you will start to play a game with yourself—just how much herxing can you tolerate? You want to kill off as much of that bacterial infection as possible, but you don’t want to overdo it.


The key is to find your line of toleration, but don’t push it too far. You will quickly learn when to suck it up and ride out the symptoms and when to back off. That is one of the interesting aspects of Lyme treatment—you get to know your body and your comfort levels very well. It may take some trial and error, but you will eventually find a balance of herxing.


Just as important as it is to “toughen up” and ride out the herxes, it is also incredibly important to give yourself breaks when needed. As much as you want to kill off the Lyme bacteria as fast and efficiently as possible, pushing yourself too far can be detrimental to your progress and short-term quality of life. A big part of living with chronic Lyme disease is learning how to manage your illness and find balance. Taking a few days off of your medication—or lowering your doses—can allow your body time to rest and detox. Work with a doctor to develop a treatment plan that accounts for the “days of” you need.


As noted before, it comes down to listening to your body. If your body is telling you to slow down and take a break, listen to it! Treating Lyme disease is a long-term game, but do your best to take care of yourself in the short term.


When Does Herxing Stop?

When antibiotic treatment is at its peak, herxing feels intense and endless. Then, you’ll start to notice your herxes become less severe. Eventually, they will subside. Then you will start a new treatment or increase your dosage and this cycle will start all over again.


When herxing stops, it is a possible indication that your current treatment has either reached its potential (killing off as much of the Lyme infection as possible) or that you need to increase the intensity of treatment. Either way, it is likely a sign of progress.

However, this is not to say that a cease in herxing means you’re in the clear. The way my doctor put it, when you experience months of sustained and diverse treatment without any herx reaction, then it is time to discuss the possibility of remission.


Herxing: It’s a Good Thing!!

Although they make you feel that much crappier, herxes are (usually) a good thing. When you herx, it means the antibiotics are doing their job. All of us who have gone through Lyme treatment laugh at the irony of it—to get better, you first have to feel worse. Like pouring salt into a fresh wound, knowing that you will inevitably feel worse before you feel better is a hard pill to swallow.


Some may disagree, but the way I look at it—after months of undiagnosed symptoms and stress—if I can do something to get better, I will. When it comes to Lyme treatment, that means enduring herxes. I’ve developed the mentality that it is something I just have to ride out. There are days when my herxes are worse than others. Some weeks the herxes put me on my ass. At some point, I turn a corner and start to feel a bit better. And eventually, it becomes more and more manageable.


When it comes to Lyme disease treatment, progress can be confusing and hard to see. Because of the nature of the disease and the time it can take to see results, it is hard to notice improvement in the short term. That is why herxing is beneficial. Once you get good at identifying and understanding your herxes, they become an indication that bacteria are being killed off. They are a bit of reassurance that your treatment is working—that all the crap you are enduring is worth it. As cheesy as it sounds, herxes can provide sense of hope.


I don’t mean to downplay or dismiss how sh***y herxing can be. It can really suck, especially on those days when you feel like you’ve taken steps backwards in your health. It can be incredibly discouraging, confusing, and just plain blah. Yes, herxes suck—but you have been strong enough to get this far. Lyme disease has not been easy up until now, and you are strong enough to get through the herxes too!

Subscribe to THOUGHTS ON HEALTH for more healing inspiration & information. Receive an occasional email with a few thoughtful blurbs on holistic health & wellness.

Unsubscribe any time. See our disclaimer and privacy policy for more detail.

  • Instagram
  • Twitter