5 Side Effects of Oral Probiotics You Should Know to Avoid

Table of Contents

Are oral probiotics safe? Yes, Oral Probiotics are generally considered to be safe for most people, but there are some potential side effects that should be taken into consideration. Not everyone will experience these side effects of oral probiotics, and they are often mild and temporary.

Unpleasant Digestive Symptoms

One of the most common side effects of Oral Probiotics is digestive upset. 

Side Effects of Oral Probiotics - upset stomach

A reason how the side effects of Oral Probiotics may cause digestive upset is due to an imbalance in gut bacteria. Our gut is home to a diverse range of bacteria, and introducing new strains through oral probiotics can disrupt this balance. The new strains may compete with the existing ones for resources, leading to bloating, gas, and discomfort. 

Additionally, certain types of probiotics may be more likely to cause digestive upset than others. For example, strains of Lactobacillus and Bifidobacterium are commonly used in probiotic supplements, but some people may be sensitive to these strains and experience digestive symptoms as a result. 

It is also possible that the dosage and timing of probiotic consumption may impact digestive symptoms. Taking too high of a dose or consuming probiotics on an empty stomach can increase the likelihood of digestive upset. 


Fermented foods like yogurt, kefir, sauerkraut, and kimchi contain bioactive compounds, including amines like histamine, tyramine, and phenylethylamine, which can trigger headaches, a potential side effect of Oral Probiotics.

Histamine, in particular, is a compound found in many foods that are high in probiotics. It is a neurotransmitter that plays a role in the regulation of the immune system and helps the body defend against infection. However, histamine can also cause inflammation and trigger allergic reactions in some people. When histamine levels become too high, they can trigger migraines and other types of headaches. 

Tyramine and phenylethylamine are also amines found in fermented foods that can cause headaches in susceptible individuals. These compounds are produced by bacteria during the fermentation process and can accumulate in high concentrations in some foods. They can trigger the release of neurotransmitters in the brain, leading to headaches and other symptoms. 

Side Effects of Oral Probiotics - headaches

While not everyone is sensitive to amines, individuals with a history of migraines or other types of headaches may be more susceptible to their effects. In some cases, eliminating foods high in amines from the diet can help reduce the frequency and severity of headaches. 

Not all fermented foods contain high levels of amines. The levels of these compounds can vary depending on the type of food, the fermentation process used, and other factors. Moreover, some studies suggest that the probiotics found in fermented foods may actually help prevent headaches and migraines by reducing inflammation and regulating immune function. 

Increased Histamine Levels

Other side effects of oral probiotics can contribute to increased histamine levels in several ways. 

Side Effects of Oral Probiotics - itching

Firstly, certain strains of probiotics have been shown to produce histamine directly. For example, the probiotic strains Lactobacillus buchneri and Lactobacillus hilgardii have been found to produce histamine in laboratory settings. When taken in supplement form, these strains can increase histamine levels in the gut and the bloodstream. 

Secondly, oral probiotics can indirectly contribute to an increase in histamine levels by promoting the growth of histamine-producing bacteria in the gut. These bacteria convert dietary histidine, an amino acid, into histamine. In individuals who are already sensitive to histamine or have histamine intolerance, this increase in histamine production can lead to a variety of symptoms. 

Lastly, Oral Probiotics can exacerbate existing allergies or intolerances to histamine. Individuals who are already sensitive to histamine or have a histamine intolerance may experience an increase in symptoms such as headaches, nasal congestion, and skin rashes when taking oral probiotics. 

However, some strains such as Bifidobacterium infantis and Lactobacillus rhamnosus GG, have been shown to decrease histamine levels in the body. 

Adverse Reactions

Adverse reactions are another common side effect of oral probiotics, including symptoms such as bloating, gas, and diarrhea.  

Side Effects of Oral Probiotics - adverse reactions

One way that oral probiotics can cause adverse reactions is through the introduction of new bacteria to the gut. While probiotics are generally beneficial, they can occasionally introduce strains of bacteria that may be harmful to certain individuals. For example, individuals with compromised immune systems may be at risk of developing infections when taking probiotics. 

Additionally, certain strains of probiotics may interact with medications or medical conditions, leading to adverse reactions. For example, some strains of probiotics may reduce the effectiveness of antibiotics or interact with immunosuppressive medications. Individuals with medical conditions such as Crohn’s disease or Ulcerative Colitis may also be at higher risk of adverse reactions to probiotics. 

Another potential cause of adverse reactions to Oral Probiotics is the presence of allergens or contaminants in the supplement. Probiotic supplements are not regulated by the FDA, and some products may contain allergens or contaminants that can trigger allergic reactions or other adverse events. 

See more:

Infection Risk in some very rare cases

In rare cases, the side effects of Dental Probiotics can include infections, particularly in individuals with weakened immune systems or other underlying medical conditions. 

Side Effects of Oral Probiotics - infection risking

One potential risk associated with the side effects of Oral Probiotics is the introduction of harmful bacteria into the gut. Although probiotics are generally considered safe, some strains of bacteria that are commonly used in probiotic supplements can cause infections in certain individuals. These infections can range from mild to severe, and in rare cases, can be life-threatening. 

Another potential risk associated with probiotics is the contamination of the supplement with harmful bacteria. Probiotic supplements are not regulated by the FDA, and some products may contain contaminants that can cause infections. This is particularly concerning in individuals with weakened immune systems, who may be more susceptible to infections. 

The risk of infection from oral probiotics is relatively low, and most healthy individuals can take these supplements without issue. However, individuals with compromised immune systems, such as those with HIV/AIDS, cancer, or other immunodeficiencies, may be at higher risk of developing infections from probiotics.  

Read more: 

Enjoy our 50% code redeem on Amazon here: