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Probiotics for Colds: Can They Help Prevent Them?

Some studies suggest daily probiotics may mean slightly fewer colds. See what the 2022 Cochrane review found, how to choose a product, and who should avoid them.

Edited by Anmar ArabPublished 24 October 2026, 7 min read
On this page
  1. Quick answer
  2. What the research says
  3. How people use it
  4. Possible side effects and interactions
  5. Who should avoid it
  6. When to see a doctor
  7. Frequently asked questions

Quick answer

Probiotics are live microorganisms, usually bacteria such as Lactobacillus and Bifidobacterium, taken in foods like yogurt or as supplements. A growing number of trials have tested whether taking them every day through the winter means fewer colds, sore throats and other upper respiratory infections.

The best summary so far, a 2022 Cochrane review, found that people taking probiotics may have somewhat fewer of these infections, slightly shorter illnesses and less need for antibiotics. However, most of the findings were rated low certainty, the studies used many different strains, and nobody can yet say which product, dose or length of use works best. Probiotics are not a treatment for a cold you already have.

For healthy adults and children they appear to be safe to try, but they are not suitable for everyone, and they should never be a reason to put off seeing a doctor about a health problem.

What the research says

The 2022 Cochrane review. Researchers Zhao, Dong and Hao updated an earlier Cochrane review and included 24 randomised trials, 23 of which (6,950 participants) could be pooled. Participants ranged from babies of one month to older adults with an average age of about 85, in countries across Europe, Asia and the Americas. Most trials ran for about three months over winter or spring. Compared with a placebo or no treatment, probiotics were linked with:

  • about 24% fewer people having at least one upper respiratory infection (16 trials, low certainty)
  • about 41% fewer people having three or more infections (4 trials, moderate certainty)
  • an 18% lower overall rate of infections (12 trials, low certainty)
  • illnesses that lasted about 1.2 days less on average (6 trials, low certainty)
  • about 42% fewer people needing antibiotics for these infections (6 trials, moderate certainty)

Side effects were no more common than with placebo and were mostly minor stomach complaints, such as wind, vomiting, diarrhoea or bowel pain. An apparent large drop in days off school or work came from a single small study and was rated very low certainty.

Why the evidence is still limited. The reviewers noted that in some trials participants may have known whether they were taking the probiotic, which can bias results, and not every trial reported every outcome. Most studies used one or two particular strains, such as Lactobacillus plantarum HEAL9 or Lactobacillus paracasei, usually at 1 billion or 100 billion colony-forming units (CFU) a day. Children mostly received them in milk-based foods, adults as powders, and older people as milk drinks or capsules. Because the products differed so much, the results cannot be applied to every probiotic on a shop shelf.

What health authorities say. The US National Center for Complementary and Integrative Health (NCCIH) describes an earlier 2015 version of the review (12 studies, 3,720 participants) as suggesting fewer and shorter infections, but with low-quality evidence. The NIH Office of Dietary Supplements (ODS) says probiotics might reduce the risk of some respiratory infections and shorten illness, and stresses that results vary because one formulation may not work like another.

How people use it

If you want to try probiotics to reduce colds, the trials offer some practical pointers:

  • Think prevention, not cure. The studies gave probiotics daily for weeks or months, usually through the cold season. There is little reason to expect a benefit from starting once symptoms appear.
  • Look for a named strain. The ODS explains that effects depend on the specific strain. A label that lists the full strain name (genus, species and strain code) lets you check whether that strain has been studied.
  • Check the CFU count. Many supplements contain 1 to 10 billion CFU per dose, and some contain far more. According to the ODS, a higher count does not necessarily mean a better product. Choose one that states the CFU count at the end of its shelf life, because live organisms die off during storage.
  • Follow storage instructions. Some products need to be kept in the fridge; others are stable at room temperature.
  • Food counts too. Yogurt made with live cultures contains bacteria that meet the definition of a probiotic. The ODS notes that many other fermented foods, such as sauerkraut, kimchi and kombucha, contain live microbes but usually not strains proven to be probiotics.
  • Give it a fair trial, then review. If after a winter you notice no difference, there is little point continuing to pay for a supplement.
Probiotics are not suitable for premature babies or for people who are seriously ill or have a weakened immune system, as rare but serious infections have been reported. Check with a doctor before using them in these situations.

Possible side effects and interactions

For most healthy people, probiotics cause few problems. The most common side effects are wind and other mild digestive symptoms, which the ODS describes as usually minor and short-lived.

NCCIH points out that few studies have looked at probiotic safety in detail, so information on how often side effects happen is limited. Possible harms in vulnerable people include infections caused by the probiotic organisms themselves. Some products have also been found to contain microorganisms that were not listed on the label.

The ODS says probiotics do not appear to interact with medicines, but antibiotics and antifungal drugs may reduce how well some probiotics work. Tell your doctor or pharmacist about any supplements you take.

Who should avoid it

  • Premature babies. NCCIH reports severe and fatal infections in premature infants given probiotics, and the US Food and Drug Administration warned health professionals about this risk in 2023.
  • People who are seriously ill or in hospital, especially those in intensive care, with a central venous line or on tube feeding. The ODS describes rare cases of bloodstream infections linked to probiotic strains in these groups.
  • People with a weakened immune system, whether from an illness or from medicines. NCCIH and the ODS both note a higher risk of serious infection in this group, so speak to your medical team first.
  • Anyone with a serious long-term health condition should check with a doctor before starting, as NCCIH advises.

When to see a doctor

Most colds clear up on their own. Adults and older children usually recover in 7 to 10 days, children under five often take 10 to 14 days, and a cough can linger for two to three weeks. Probiotics should never be a reason to delay getting help. Contact a doctor if:

  • symptoms last more than three weeks
  • symptoms suddenly get worse
  • you have difficulty breathing
  • you develop chest pain or cough up bloodstained mucus
  • you are worried about a baby, an older person or someone with a long-term illness such as a lung condition

Frequently asked questions

Can probiotics cure a cold once I have one?

No. The trials looked at taking probiotics regularly to reduce the chance of infections, not at treating a cold after it starts. Rest, fluids and simple pain relief remain the usual self-care for a cold.

Is yogurt as good as a probiotic supplement?

Not necessarily. Yogurt with live cultures contains helpful bacteria, but its strains and amounts may differ from those tested in the trials. Some of the studies in children did use probiotic milk-based foods, so a yogurt or fermented milk drink that names a studied strain is a reasonable option.

Are probiotics safe for children?

The Cochrane review included healthy children from one month to eleven years old, and side effects were mostly mild stomach upset. Even so, it is sensible to choose a product made for children and to ask a pharmacist or doctor first, especially for babies. Premature babies should not be given probiotics unless a medical team advises it.

Which probiotic strain is best for colds?

There is no clear answer yet. The trials used many different strains, and the reviewers called for larger, well-designed studies to find out which work best. A product naming a strain that has been tested in trials is more likely to be worthwhile than one with no strain information.

References

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