Is Kefir Good for Diarrhea?

Partly: if you tolerate dairy, kefir may be easier to digest than milk because fermentation reduces its lactose, but it is not a proven treatment for diarrhea.

Is kefir a good choice when you have diarrhea?

Kefir is an optional food, not a dependable diarrhea remedy. In the available randomized trial, kefir did not prevent antibiotic-associated diarrhea in young children; the trial did not test whether it could treat diarrhea that had already started.

If you usually tolerate dairy, you can try a small amount and stop if it makes you feel worse. It is also reasonable to skip kefir while you recover. For other food choices, see the best foods for diarrhea.

Replacing lost fluid matters more than adding kefir. Diarrhea has many possible causes, and a food that feels comfortable for one person may aggravate symptoms for another.

How might kefir affect diarrhea?

Kefir is fermented milk. During fermentation, microbes break down some of the milk’s lactose, so kefir may be easier to digest than ordinary milk for some people who have trouble with lactose. It still contains lactose, however, and diarrhea can temporarily make lactose harder to tolerate.

Kefir can also contain live microbes that interact with the gut. That does not mean every kefir product has the same effects or that its microbes will improve diarrhea. The cultures and their amounts can vary between products, and the effects of a particular product need to be studied.

Some people may experience gas, bloating or looser stools after kefir, particularly if they are sensitive to dairy. If that happens, avoid it rather than trying to build up a tolerance during an episode of diarrhea.

What does the evidence say about kefir and diarrhea?

A 2009 randomized controlled trial studied a commercial kefir product in 125 children aged 1 to 5 years who were taking antibiotics. The researchers compared kefir with a matching heat-treated placebo over a 14-day follow-up. Kefir did not significantly reduce the rate of antibiotic-associated diarrhea.

This is direct evidence about kefir, but it addresses prevention in a specific group. It does not establish whether kefir treats existing diarrhea, helps adults or has an effect on diarrhea from other causes. The result also does not show that kefir necessarily causes diarrhea.

The label “live cultures” is not proof that a product will help. Benefits reported for a different probiotic or fermented food cannot automatically be assigned to kefir.

How can you use kefir safely during diarrhea?

If you want to try kefir, choose a plain product made from pasteurized milk and check the label for added sugar. Store it as directed on the package. Avoid kefir made from unpasteurized milk because of the risk of harmful germs.

Try a small amount with food if you feel able to eat. There is no established dose or schedule for treating diarrhea with kefir. Stop if it worsens cramping, bloating or loose stools, and do not force yourself to drink it if you feel nauseated.

Drink fluids to replace losses. An oral rehydration solution, prepared according to its label, can replace both fluid and electrolytes; it is especially useful when losses are substantial. For more hydration choices, see the best drinks for diarrhea. If you have kidney disease, heart failure or a prescribed fluid restriction, ask your clinician how to replace fluids safely.

For an infant, continue breastfeeding or usual formula and contact a clinician for guidance. Do not substitute kefir for an infant’s usual feeds or for an oral rehydration solution.

Who should be careful, and when should you get medical help?

Avoid dairy kefir if you have a milk allergy. Lactose-free dairy kefir is not necessarily safe for a milk allergy because it can still contain milk proteins. If you have lactose intolerance, kefir may still cause symptoms even though fermentation reduces its lactose.

Ask a clinician before using kefir with live cultures if you have a weakened immune system. Contact a clinician promptly about diarrhea in an infant or young child, during pregnancy, in an older adult, or in someone with a weakened immune system. An adult should also contact a clinician if diarrhea lasts more than 2 days, or sooner if it worsens.

Seek urgent medical care for bloody or black stools, severe abdominal pain, fainting or confusion, or if you cannot keep fluids down. Very little urine and marked dizziness can also signal serious dehydration and need prompt assessment.

If diarrhea begins during or after antibiotics, contact the prescriber, especially if symptoms are severe or accompanied by fever. Do not stop a prescribed antibiotic without speaking to the prescriber.