Can probiotics cause flu-like symptoms

Can Probiotics Cause Flu-Like Symptoms? (EXPLAINED!)

When you think of probiotics, the last thing you probably expect is to feel sick. But there are some reports that some probiotic supplements can cause flu-like symptoms in some people.

So what’s going on here?

And more importantly, should you be worried about taking probiotics?

Key Highlights
  • Probiotics can cause flu-like symptoms in some people, but it’s usually a sign that they’re working to detox your body and get rid of bad microbes.
  • The flu-like symptoms are caused by the Herx Reaction, which occurs when bad bacteria, parasites, and yeast die from the effects of probiotics.
  • Most people aren’t likely to experience flu-like symptoms from taking probiotics, but if you do, it’s usually not something to worry about unless you continue to feel bad even after a week.
  • Probiotics can help your body fight against the flu and the common cold by improving the health of your immune system.
  • Click here for the BEST PRICE of our recommend probiotics supplement.

How does the Herx Reaction work, how can you tell probiotics are not really making you feel worse, and do you need a different treatment to get rid of these flu-like symptoms?

Keep reading to learn about what I learned from researching in-depth on this topic.

Flu-Like Symptoms Caused By Probiotics

Numerous studies have long shown that probiotics can be good for our health and prevent various illnesses. A 2009 clinical trial even showed that children given a daily dietary supplementation of probiotics for 6 months might have reduced the incidence of cough, fever, runny nose, and similar flu symptoms.

flu-like symptoms

But why are there some reports of people experiencing flu-like symptoms after using probiotics?

That’s known as the Jarisch-Herxheimer Reaction or, simply, the Herx Reaction, explains Zuma Nutrition here.

Also called the “die-off,” Herx Reaction causes flu-like symptoms to appear as bad bacteria, parasites, and yeast (like Candida) die from the effects of probiotics.

Yes! It is believed that the flu-like symptoms that people get with probiotics use could be a sign that these are actually working. 

Researcher Adolf Jarisch (in 1895) and German dermatologist Karl Herxheimer (in 1902) both noticed that many of their patients being treated for syphilis experienced various flu-like symptoms.

Zuma Nutrition and Craft Cultures list the Herx Reaction symptoms as follows:

  • Chills or fever
  • Sore throat
  • Sweating
  • Headache
  • Nausea
  • Dizziness 
  • Body aches
  • Joint and muscle pain
  • Fatigue
  • Swollen glands
  • Bloating, gas, constipation, or diarrhea
  • Bad breath
  • Body itchiness, hives, or rashes
  • Recurring vaginal, prostate, and sinus infections
  • Skin breakouts

Zuma Nutrition explains that further studies based on these researchers’ observations later showed these symptoms were caused by the toxins and various chemicals released by the dying microorganisms.

As their patients’ bodies were getting detoxed by the treatment, the parasites and bad, pathogenic bacteria and yeast gave off proteins, toxins, and oxidizing agents that increase inflammatory cytokines.


Most people aren’t likely to experience getting flu-like symptoms from taking probiotics. But if you do have them, it’s usually not something to worry about unless you continue to feel bad even after a week.

Let’s take a look at each of the symptoms to determine why they could happen even if you were healthy and didn’t feel the least bit sick before taking probiotics.

Can Taking Probiotics For The First Time Give You Flu-Like Symptoms?

The flu-like symptoms listed above were often experienced by those who took probiotics for the first time.

If your symptoms persist for over a week, then these might be caused by an underlying condition instead of just a “die-off” from probiotics.

Be sure to consult your doctor.

According to Body Logic MD, it’s also possible that a low-quality probiotic might be causing this issue. Considering that the FDA doesn’t regulate probiotics, there’s really no telling whether you’re taking a good one.

Often, you just have to go with your gut feeling, pun intended, in choosing high-quality probiotics. Well-known and popular brands might be the obvious choice, but you can also find my recommendations below.

Can Probiotics Give You A Fever?

Yes, probiotics can you fever. Fever is listed as one of the most common symptoms of Herx Reactions.

It’s typically going to be low-grade fever (100.4 and 102.2°F) and some chills. 

While these could be expected during the “die-off” from probiotics, repeatedly getting a high fever (temperatures higher than 103°F) could be a sign of an infection. Call or visit your doctor.

Can Probiotics Cause Sinus Infections & A Runny Nose?

Yes. Some patients might experience getting sinus infections from the “die-off.” According to Craft Cultures, this might even recur on a regular basis.

Histamine release from an allergic reaction to the probiotic supplement or food might also cause a runny nose or lead to sinus infections. 

Some live microorganisms or other components in probiotics might trigger allergic reactions. For example, some probiotic drinks are milk-based, and milk is a common allergen.

According to Healthline, these are some of the common histamine-producing probiotic strains:

  • Streptococcus thermophilus
  • Lactobacillus hilgardii
  • Lactobacillus helveticus
  • Lactobacillus buchneri

It’s best to check the label and avoid certain products if you have known allergies to their components.

While allergic reactions are different from the flu, both can cause a runny nose. 

Be careful because you can experience both an allergic reaction and Herx Reaction to the probiotic.

Can Probiotics Make You Dizzy?

According to Dr. M. Elizabeth Swenor of Henry Ford Health, there could be many different reasons why probiotics make you feel dizzy. 

One of these theories is that probiotics might cause intestinal inflammation, which can subsequently affect the neuroendocrine system.

Because of the mind-gut connection, you could feel dizzy even if the probiotics only affected your gut system.

Can Probiotics Cause Fatigue And Brain Fog?

Following Dr. Swenor’s explanation above, probiotics can potentially cause fatigue and brain fog due to the issues with intestinal inflammation through your mind-gut connection.

She also suggests seeking your doctor’s advice before taking probiotics if you have any digestive issues so you can avoid getting these symptoms.

Can Probiotics Make You Feel Tired and Unwell?

When you have the flu, you feel fatigued and unwell. 

Some people who took probiotics also experience a similar thing. Zuma Nutrition and Craft Cultures list these as among the common Herx Reactions.

But aside from feeling tired due to the “die-off” chemicals released by these bad bacteria, you might have an increased risk of feeling this flu-like symptom if you have an underlying medical condition. 

Cleveland Clinic warns that you should avoid taking probiotics if you have the following conditions because they can make you feel worse:

  • Weakened immune system (e.g., undergoing chemotherapy or similar treatments)
  • Critical illness
  • Recent surgery

Probiotics As Treatment For Flu

Although I’ve explained to you that probiotics can cause flu-like symptoms, the good news is that it’s actually rare. Most people are going to be fine while taking probiotics or will just experience mild symptoms that could usually go away after a few days.

probiotics illustration

Another good news is that studies have actually shown that probiotics can be a good form of treatment for flu.

For example, the 2009 clinical trial mentioned above showed that daily dietary supplementation of probiotics in children for 6 months may have helped reduce the incidence of flu, cough, fever, and runny nose. 

According to GP (General Practitioner) and Medical Director of Healthspan, Dr. Sarah Brewer, probiotics can help your body fight against the flu and the common cold by improving the health of your immune system.

Can Probiotics Prevent Common Colds & Flu?

Everyday Health points out that studies on probiotics have not yet clinically proven their effectiveness against the flu, but they do have promising results, especially when it comes to improving your immune system against respiratory illnesses.

They shared a list of the probiotics that might help boost your immune system to fight respiratory illnesses such as the flu and common colds:

  • Lactobacillus delbrueckii subsp. bulgaricus
  • Lactobacillus bulgaricus
  • Streptococcus thermophilus
  • Lactobacillus acidophilus
  • Bifidobacterium 

My Recommendations: Probiotics To Help Strengthen Immunity Against Flu

I recommend these two probiotic supplements: Probiology Gut+ and Bauer Nutrition Biotics 8. They’re both shelf-stable probiotics.

While they don’t directly fight the flu, these probiotics can help your immune system get ready for any form of infection, including respiratory illnesses. Remember, prevention is several times better than cure.

1. Yourbiology Gut+

Yourbiology Gut+ contains four probiotic strains, including Lactobacillus acidophilus and Bifidobacterium listed above as recommended strains for boosting your immune system.

2. Bauer Nutrition Biotics 8

Bauer Nutrition Biotics 8 contains 10 carefully chosen probiotic strains, including Lactobacillus acidophilus and three Bifidobacterium strains (Bifidobacterium bifidum, Bifidobacterium longum, and Bifidobacterium breve) which are also listed by Everyday Health for immune system health.

Wrap up

Probiotics are a great way to improve gut health, but they can also cause flu-like symptoms when you first start taking them. This is actually a good sign because it means the probiotics are working and fighting against bad bacteria in your gut.

Make sure to drink plenty of water and give your body time to adjust to the probiotics before giving up on them. Have you had any experience when you started taking probiotics supplements?

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