Probiotics and eczema: what the studies show so far

Somewhere between the moisturizer aisle and the vitamin aisle, you’ll find probiotics with eczema-friendly packaging and a friend who swears they worked for her nephew. The idea is appealing: fix the gut, calm the skin, no creams involved. The research behind it is real, but it’s early, mixed and easy to oversell. Here’s where things stand, and what a probiotic label can legally tell you in Canada.

What are probiotics, and what’s the gut–skin idea?

Probiotics are live bacteria (occasionally yeasts) taken by mouth in the hope of improving the community of microbes living in the gut, the gut microbiome. The most studied families are Lactobacillus and Bifidobacterium, and within each family there are many strains, which matters more than you’d think.

The link to skin runs through the immune system. A 2025 review in the International Journal of Molecular Sciences describes the gut–skin axis this way: the gut and the skin communicate in both directions, and when gut bacteria are out of balance (dysbiosis, in the jargon), they produce fewer of the protective compounds that help keep immune responses in check. That imbalance can be felt at the skin as more inflammation. The review also argues that early life is when the microbiome shapes the immune system most, which is where the hope of prevention comes from.

That’s the theory, and it’s biologically plausible. Plausible isn’t the same as proven, so let’s look at the trials.

Treating eczema that’s already there

The best summary of the evidence remains a 2018 Cochrane review, which pooled 39 randomized trials with 2,599 participants, most of them children, taking Lactobacillus or Bifidobacterium strains alone or in combination for four weeks to six months.

The result was sobering. Symptoms rated by patients or parents were only 0.44 points lower on a 20-point scale, a difference too small to notice. There was no evidence that probiotics improved quality of life. Severity scored by investigators fell by about 3.9 points, well short of the 8.7 points considered clinically meaningful. Cochrane’s conclusion: the use of probiotics for treating eczema is currently not evidence-based.

Newer analyses are a little warmer, but not much. A 2023 meta-analysis in Clinical and Translational Allergy looked at nine trials in 1,000 children and found that single-strain probiotics, particularly certain Lactobacillus strains, produced a modest fall in severity scores, with more benefit in children over three. The authors still called the evidence limited, pointing to small samples and inconsistent designs. The 2025 review reached a similar place: modest reductions in some trials, but so much variation between studies that firm recommendations aren’t possible, and probiotics should be seen as an add-on to standard care, never a replacement.

So if your child is already using a probiotic and seems fine, there’s no reason to panic. But don’t drop the moisturizer or the prescribed cream for it, and don’t expect it to do the heavy lifting.

Preventing eczema in babies at risk

Prevention is where the early excitement came from, and where the disagreement is sharpest.

A few years ago, an international allergy guideline suggested probiotics for prevention in families at high risk of allergy, mainly because pooled trials showed fewer cases of eczema, while acknowledging that the quality of that evidence was limited.

Then a 2018 meta-analysis in Nutrients tested the single most-studied strain, a Lactobacillus rhamnosus strain known as GG, across five randomized trials with 889 mother–infant pairs. It found no difference in the risk of eczema between babies whose families took the probiotic and those who didn’t, whether it was given in pregnancy, during breastfeeding or to the infant. The authors concluded their analysis did not support using that strain to reduce eczema risk, and said guidelines should be revised to say which strains, if any, actually work.

The 2025 review adds a nuance: across trials, giving probiotics to the mother before and just after birth looked more protective than starting later, and multi-strain mixtures looked more consistent than single strains. That may be true, or it may reflect which trials happened to work; the review itself calls the overall certainty weak to suggestive.

The honest summary for a parent: some strains, given at some times, may reduce eczema in some high-risk babies, and the most famous strain probably doesn’t. If your family has a strong history of eczema, asthma or allergies, it’s a fair question to bring to your doctor or midwife during pregnancy, not something to decide from a label.

Are they safe?

Reassuringly, yes, for healthy children. Cochrane found no evidence that probiotics increased the risk of adverse events in the trials it reviewed; the occasional complaint was mild digestive upset. The 2025 review likewise calls them generally well tolerated.

The caveats are about who the trials didn’t include. Premature babies, children with serious underlying illness and children with weakened immune systems weren’t the population studied, and live bacteria are a different proposition for them. In those situations, ask your doctor before giving any probiotic.

What an NPN on a probiotic means in Canada

Here’s the part that’s most useful at the store. In Canada, probiotics sold as capsules, drops or powders are natural health products, and they must carry an eight-digit Natural Product Number, or NPN, on the label. Health Canada’s licensed products database explains that a licence means the product has been assessed as safe, effective and of good quality under its recommended conditions of use, for the claims on its label.

The key words are “for the claims on its label”. Most probiotics are licensed under Health Canada’s probiotics monograph, a standard document that lists which bacteria are accepted and which claims they may make. As of the 2026 version, the general claims allowed are “source of probiotics”, “helps support intestinal/gastrointestinal health” and “could promote a favourable gut flora”. A few specific strains have additional claims, all of them about diarrhea or stomach infections. There is no eczema claim in the monograph.

So when you see an NPN on a probiotic, it tells you Health Canada has reviewed the product’s safety, quality and its gut-health claim. It does not tell you the product has been shown to prevent or treat eczema, and a product that says it does on the front of the box is making a claim its licence probably doesn’t cover. If you want to compare products whose claims have been reviewed, the supplements page on this site is the place to look.

What to do if you’re tempted to try one

• Talk to your doctor or pharmacist first, especially for a baby, and always for a premature or medically fragile child.
• Keep doing the things with strong evidence: daily moisturizer, gentle bathing, trigger-spotting and prescribed treatment for flares.
• Look for the NPN and read the actual claim on the label, not the marketing.
• Give it a defined trial, a couple of months, and judge honestly whether anything changed. Eczema waxes and wanes on its own, which is how many “it worked” stories are born.
• Stop and see your doctor if the eczema is getting worse, is costing your child sleep, or shows signs of infection: oozing, yellow crusts, pus, pain, small blisters or fever.

Probiotics are a reasonable scientific idea with, so far, weak results: little or no benefit for treating eczema according to Cochrane, and mixed, strain-dependent results for prevention. They appear safe for healthy children. And in Canada, the NPN on the box is a promise about gut health and manufacturing quality, not about your child’s skin.