Can Friendly Gut Bacteria Help a Jaundiced Newborn Recover Faster?

What a 2026 study of probiotics added to light therapy found for full-term babies with jaundice

When a newborn develops jaundice — the yellow tint of the skin and eyes caused by a normal but temporary buildup of a substance called bilirubin — the usual treatment is phototherapy, a special blue light that helps the body clear it. A new study asked whether adding friendly gut bacteria, known as probiotics, could help babies recover a little faster. The answer was cautiously encouraging: full-term babies who received a two-strain probiotic alongside light therapy cleared their jaundice somewhat more quickly and went home about a day sooner.

Why jaundice matters and how it has long been treated

Most parents of a newborn will hear the word "jaundice." It happens because a baby's young liver cannot yet keep up with clearing bilirubin, a yellow pigment made when the body recycles old red blood cells. In most babies it is mild and fades on its own, but when levels climb too high the pigment can, in rare cases, harm the developing brain — so doctors watch it closely and treat it when it crosses established limits. For decades those limits, and the decision of when to start treatment, have followed national guidelines; in the United States the current standard comes from the American Academy of Pediatrics [1].

The treatment itself, phototherapy, has been a mainstay for more than fifty years. Blue light changes the shape of the bilirubin in a baby's skin so the body can flush it out. It is safe and effective, which is why it is used so widely, but it is not entirely without downsides: it can cause loose stools, interrupt feeding, and briefly separate a baby from a parent's arms, all of which can be stressful during an already anxious time [2]. For years, doctors and families have wondered whether anything could make phototherapy work a little faster or a little more gently.

A new idea: look to the gut

Part of the answer may lie somewhere unexpected — the baby's gut. Scientists have learned that light therapy disturbs the community of bacteria living in a newborn's intestines, reducing the helpful kinds and their variety [3]. Separately, babies with jaundice tend to have fewer of a beneficial family of bacteria called Bifidobacterium to begin with [4]. This matters because a large share of a baby's bilirubin is actually reabsorbed from the intestines rather than removed. Bacteria that keep things moving through the gut and help package bilirubin for disposal could, in theory, help the body clear it faster. That reasoning is what led researchers to test probiotics — live helpful bacteria given by mouth — as a partner to phototherapy [5].

The idea is not brand new. Earlier reviews that pooled many small studies suggested that adding probiotics to standard jaundice care improved results [6], and a later review of randomized trials likewise found shorter treatment and hospital times — but the studies were small and used many different bacteria and doses, so the evidence never felt solid enough to change everyday care [7]. The new study set out to do it more carefully.

What the researchers did

Researchers in Shanghai, China, ran a randomized controlled trial — the kind of study where babies are assigned by chance to different treatments so the groups can be compared fairly — at the neonatal unit of the Sixth People's Hospital affiliated to Shanghai Jiao Tong University, enrolling babies between September 2020 and October 2023 [5]. Seventy-nine healthy full-term newborns who needed phototherapy were divided by chance into four groups: light therapy alone, or light therapy plus one of two probiotic strains (called M-16V and Bb-12), or light therapy plus both strains together [5]. The probiotics were given once a day and continued for a month after the baby went home. The groups were similar at the start, so any differences afterward could reasonably be linked to the probiotics [5].

What they found

The babies who received both probiotic strains did best. They passed stool a bit more often — which the researchers came to see as a good thing, because it is one of the main ways bilirubin leaves the body — and by the end of treatment their bilirubin levels measured through the skin were lower than in the light-only group [5]. On average, babies in the two-strain group went home about a day sooner. Some of these differences were clear and statistically convincing, while others were smaller and did not quite reach the threshold scientists use to be confident, so the picture is promising rather than definitive [5]. Reassuringly, the babies grew normally, and the researchers reported no harmful effects they could attribute to the probiotics [5].

The study also looked under the hood. Laboratory analysis showed that the probiotics helped rebuild the healthy gut bacteria and variety that light therapy had reduced, and increased calming, anti-inflammatory substances in the gut — the kind of natural signals that help strengthen the intestinal lining and quiet inflammation [8], [5]. In other words, the babies' faster recovery came alongside a measurable improvement in their gut health.

Putting the numbers in perspective

It helps to picture what these findings looked like day to day. In the group that received only light therapy, babies had bilirubin readings on their skin of about 6.1 at the end of treatment; in the group that also received both probiotics, the readings were closer to 4.4 [5]. The probiotic babies also passed stool a little more often — on the order of four times a day rather than three — and this extra stooling is not a problem to be managed but the very route by which the yellow pigment leaves the body [5]. The average hospital stay shrank from a little under five days to around three and a half in the two-strain group [5]. These are modest, real-world differences: not a dramatic overnight cure, but the kind of gentle nudge that could mean one less day in the hospital and a quicker return home. Because the study followed fewer than eighty babies at a single hospital, the smaller differences could still be down to chance, which is exactly why the researchers themselves describe the results as encouraging rather than settled [5]. Parents reading headlines about probiotics and jaundice should hold onto that balance — a promising direction, measured honestly.

What this means for families

If your baby needs phototherapy, the most important message is that light therapy remains the trusted, effective treatment, and this study does not change that. What it adds is early, hopeful evidence that a specific pair of probiotics might help healthy full-term babies clear jaundice a little faster and leave the hospital a little sooner, while supporting their gut in the process. It is not yet a routine part of care, and it has not been tested in premature or very small babies, where the situation is different and safety must be judged separately. If you are curious about probiotics for your baby, the right step is to ask your pediatrician rather than starting anything on your own.

It also helps to know that a baby's gut bacteria are shaped most of all by everyday things — how a baby is born and, above all, how a baby is fed. The bacteria present from the very first days are linked to jaundice risk [9], breastfeeding is associated with its own gentle form of jaundice [10], and the causes of significant jaundice vary widely from place to place [11]. Delivery method and nutrition strongly influence which bacteria take hold [12], and breastfeeding in particular helps restore healthy gut bacteria [13] — a reminder that feeding support is one of the most powerful and freely available tools for a baby's health, with or without any supplement.

What researchers are working on next

Because this was a single hospital's study with a modest number of babies, and because some of the people who ran it were connected to the company that makes the probiotics, scientists will want to see the results repeated. The next step researchers are working toward is larger studies across several hospitals, run independently, that test one clear question at a time and follow children long enough to know whether faster clearing of jaundice makes any lasting difference to their development. Until those studies arrive, the honest takeaway is warm but measured: this is a genuinely encouraging early sign that supporting a baby's gut could make a proven treatment work a little better, and a good reason to keep asking questions — not yet a reason to change what happens at the bedside.

References

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  9. Dong T, Chen T, White RA, et al. Meconium microbiome associates with the development of neonatal jaundice. Clin Transl Gastroenterol. 2018;9(9):182. doi:10.1038/s41424-018-0048-x ↩
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