Probiotics are live microorganisms that are intended to provide health benefits when consumed in adequate amounts. These beneficial bacteria can be found in a variety of foods and supplements and have gained popularity in recent years as a natural way to promote digestive health and boost the immune system. While probiotics can offer numerous benefits, they can also have side effects that should be considered. In this guide, we will explore the pros and cons of probiotics, how they work, and what to look for when choosing a supplement.

Understanding the Probiotic Overdose

Probiotic overdose may occur if you consume excessive probiotics, either through foods or supplements. While the recommended dosage varies depending on the product and the individual, exceeding the recommended dose can lead to an overdose.

Factors influencing probiotic overdose are as follows,

Overconsumption of probiotic-rich foods: Consuming too much yoghurt, kefir, kombucha, sauerkraut, and other fermented foods that contain probiotics can lead to an overdose.

Excessive use of probiotic supplements: Taking more than the recommended dose of probiotic supplements can increase your risk of overdose.

Combination of different probiotics: Combining different types of probiotics can also increase your risk of an overdose. Each probiotic strain has its own unique properties and effects on the gut microbiome. Taking multiple strains at the same time can cause an imbalance in the gut microbiome and increase the risk of an overdose.

Individual variation in sensitivity: Some individuals may be more sensitive to probiotics than others. Individuals with a weakened immune system or a history of digestive issues may be at a higher risk of an overdose.

Age and background health status: Age and health status can also influence the risk of a probiotic overdose. Children, elderly individuals, and individuals with underlying health conditions particularly with weakened immune systems may be more susceptible to an overdose.

What are the symptoms of Probiotic overdose and why do they occur? 

Gut symptoms

Why it occurs?

The major site of action of probiotics we consumed is mainly in the gut. And hence, when consumed in large amounts as part of the diet or taken in high doses as a supplement, the most noticeable symptoms occur mainly in the gut. Symptoms may differ according to variation in the individual gut microbiota content.

How would I feel or suffer? 

The most common symptoms include abdominal discomfort which includes cramps, bloating, diarrhoea and nausea in some cases. 


Although such symptoms are common, they are generally mild and do not need additional medication. Symptoms usually outgrow by reducing the dose of probiotics or stopping for some weeks. You can reintroduce probiotics from low doses when the symptoms go off. 

Allergic Reactions 

The science behind rash and allergy

Before we talk about allergic reactions caused by probiotics, it is noteworthy that rash and allergic reactions are caused by histamines which are produced by our body in order to protect ourselves from a foreign body or external insults. Its main action is the dilation of our blood vessels and can cause redness and swelling in the affected area, and can also trigger allergy symptoms such as itching, watery eyes, runny nose, or even trouble breathing in severe cases.

How this is linked to Probiotics? 

Certain bacterial strains like Lactobacillus buchneri, Lactobacillus helveticus, Lactobacillus hilgardii and Streptococcus thermophilus used in probiotic supplements and fortification of food can produce “histamine” inside our gut and stomach, which can lead to the allergic or allergy like symptoms. 

What should I concern about?

Since this side effect is presented by some individuals, it is not very common since it depends on the susceptibility of the individual as well as the ability to break down the histamine produced in the body in response to probiotics by the body’s natural enzymes.

Immune system abnormality

While probiotics are known for their immune-boosting properties when taken in appropriate doses, taking too many probiotics can have the opposite effect. Some concerning health issues include allergic reactions and frequent infections.

Why this occurs? 

Excessive probiotic consumption can cause an imbalance in the gut microbiome, which regulate the immune system. 

Studies have found that probiotic overdose can cause changes in the immune system, including a decrease in the production of immunoglobulin A (IgA), a key component of the immune system which helps protect the body from infections.  

Consult with your doctor if you have any immune disease

It is important to take probiotics in appropriate doses and to consult with a healthcare professional before taking them, especially if you have a weakened immune system or a history of immune system problems. Your healthcare professional can help you determine the appropriate dose and type of probiotics for your individual needs.

Mood Changes

Effect on Gut-Brain Axis

The gut-brain axis is a two-way communication system between the gut and the brain. It is a complex network of nerves, hormones, and neurotransmitters that connects the digestive system to the central nervous system. The gut microbiome plays a crucial role in the gut-brain axis, and an imbalance in gut bacteria can affect brain function and behaviour.

Bi-directional effects

In the same way as probiotic deficiency, excessive probiotic consumption can have adverse effects on the gut-brain axis since it is maintained on an equilibrium of gut microbiota. Probiotic overdose can cause an imbalance in the gut microbiome, which can affect neurotransmitter production and lead to mood changes such as anxiety and depression.


In addition, probiotic overdose can affect the production of short-chain fatty acids (SCFAs) in the gut. SCFAs are produced by gut bacteria and play a crucial role in regulating the gut-brain axis. An imbalance in SCFA production can lead to gut and brain dysfunction.

Mood Problems while on probiotics? Always consult a doctor

If you have a history of mental health disorders or experiencing mood problems while taking probiotics, consult with your doctor for the appropriate dose and type of probiotics for your individual needs.

How to avoid Probiotic overdose?

Know your food 

It is important to be aware of which foods are rich in probiotics so that you can take care of yourself not to consume too much of them. 

When taken as supplements, always follows the recommended daily dose. Do not exceed the recommended dose, even if you feel like you need more or feel palatable for you. The latter is more common in probiotic supplements for children. 

Take probiotics with food

Taking probiotics with food can help improve their absorption and reduce the risk of digestive issues as well as can avoid the effects of being overdosed. 

Consider a targeted probiotic supplement

Some probiotic supplements are designed for targeted populations with specific health conditions, such as digestive disorders, urinary tract infections or vaginal health. Such specifically tailored probiotics might be a better choice than a general over-the-counter probiotic supplement.

Monitor the symptoms

If any of the symptoms mentioned above come up while taking probiotics, you should consider stopping the probiotics even for a while and consider consulting with your doctor if the symptoms are discomfort enough to affect your well-being. 

Discuss with your doctor about background medical history

If you have any previous illness or medical condition, it is advisable to consult and discuss with your doctor before taking probiotic supplements to avoid unwanted side effects. 

Take-Home Message

  • Probiotics can be a useful addition to a healthy lifestyle, but they should be used cautiously while taken as supplements or as part of our diet. 
  • By understanding the potential benefits and risks of probiotics, you can make an informed decision about whether they are right for you. 
  • It is advisable to be aware of potential signs and symptoms of probiotic overdose as well as how to get rid of those side effects. 
  • Always consult with your healthcare provider before starting any new supplement regimen especially if you have any underlying medical conditions or if you experience any side effects.