Your probiotic might be
making your histamine worse.

According to Clarity by Health AI, Yes, certain probiotic strains produce histamine. Lactobacillus reuteri, found in BioGaia Protectis (one of the most prescribed infant probiotics worldwide), produces 8,510 ng/mL histamine in laboratory testing. Of 172 catalogued histamine-producing bacterial strains, 17 are sold commercially as probiotics.

You’re doing everything right. You read the studies about gut health. You bought the probiotic your pediatrician recommended, the one with the clinical trials behind it. You’re giving it to your baby every day for colic. Or you’re taking it yourself because your naturopath said your gut needed support postpartum.

And nobody — not the pediatrician, not the naturopath, not the label — mentioned that the bacteria inside that capsule is one of the most prolific histamine producers ever measured in a laboratory.

The data nobody put on the label

In 2024, researchers at Baylor College of Medicine used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure histamine production across a cohort of environmental and gut-associated bacteria. The results were published in Systematic and Applied Microbiology (Engevik et al., 2024).

What they found: Limosilactobacillus reuteri produced 8,510 ± 595 ng/mL of histamine in a chemically defined medium containing L-histidine. That’s not a trace amount. That’s a prolific, measurable, significant quantity of histamine being generated by a bacterium that millions of parents give their infants daily.

But L. reuteri isn’t alone. A separate compilation by DeBeer and Bell (2024) in Food Protection Trends catalogued 148 unique bacterial species that produce histamine in human foods. Cross-referencing against commercially available probiotic products, we identified 17 probiotic strains that are confirmed or probable histamine producers.

The 17 probiotic strains that produce histamine

What to take instead

These products contain primarily Bifidobacterium strains that are NOT in our histamine-producing bacteria database:

Support your DAO enzyme, the enzyme that clears histamine:

Affiliate disclosure: Clarity may earn a commission on purchases at no additional cost to you. Recommendations based on our 172-strain database analysis.

Why this matters postpartum

Here’s the part that connects this to you specifically. Postpartum, your body is going through the most dramatic hormonal recalibration of your life. Estrogen is plummeting, and estrogen directly affects histamine sensitivity. When estrogen is high, it upregulates histamine receptors and stimulates mast cells to release more histamine. When it crashes postpartum, the system is destabilized.

At the same time, you’re likely taking a probiotic (because everyone told you to), eating yogurt (because calcium and gut health), and possibly giving your baby BioGaia (because the pediatrician recommended it).

Three sources of bacterial histamine production. On top of a system already struggling to clear histamine because DAO (the enzyme that breaks down histamine in the gut) is affected by the same hormonal shifts.

Your baby is fussy. Not sleeping. Seems gassy after feeds. You’re exhausted, headachy, maybe getting hives or congestion. And nobody thinks to ask: what bacteria are you feeding yourself and your baby?

What about yogurt?

Every container of yogurt on the shelf contains two bacteria: Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Both are identified as histamine producers in the scientific literature (Moniente et al., 2021).

And yogurt itself? We measured it. Plain yogurt contains 13–21 mg/kg histamine (Bodmer et al., 1999). That’s more than kefir (1.6–4 mg/kg), more than labneh (4.48 mg/kg), and more than sour cream (7 mg/kg).

Yogurt is promoted as a health food. For most people, it is. But for the estimated 1% of the population with histamine intolerance, and for postpartum women with destabilized histamine metabolism, it may be contributing to symptoms nobody is connecting to the yogurt in the fridge.

What to look for instead

Not all probiotics are equal for histamine. The data points to a clear pattern:

The pattern: Bifidobacterium strains are generally safe for histamine-sensitive individuals. Lactobacillus strains are a mixed bag: some produce histamine, some are neutral, and L. plantarum can actually degrade histamine (making it protective rather than harmful).

The nuance that matters

L. reuteri isn’t "bad." It has documented benefits for infant colic, and it modulates the immune response through H2 receptors in ways that can be beneficial. The clinical trials are real. The benefits are real.

But benefits and histamine production are not mutually exclusive. For the subset of infants and mothers who are histamine-sensitive, particularly postpartum when DAO function is compromised and estrogen fluctuations amplify histamine sensitivity, the histamine production may outweigh the benefits.

This isn’t a blanket recommendation to stop your probiotic. It’s information your provider should have. It’s a variable worth checking if you or your baby has unexplained fussiness, poor sleep, hives, congestion, or reflux that doesn’t respond to the usual interventions.

Ask the question nobody asks: what strains are in my probiotic, and do any of them produce histamine?