Millions of friendly bacteria live in our intestines. They’re essential to digestion. But diarrhea can throw off the balance of these microbes in your gut. Probiotics, doses of helpful bacteria or yeasts, may help get things back on track and treat some kinds of diarrhea, studies suggest.
One source of probiotics you might know about is yogurt, which is made by adding bacteria to milk. The same microbes may help keep your intestines healthy. There are dozens of other kinds that may have health benefits, too.
Not all probiotics help diarrhea. And only certain types of the condition seem to get better when you take them. So which ones may help and when?
Diarrhea in Children
Some of the best evidence on the benefits of probiotics comes from studies of diarrhea in children, especially cases caused by rotavirus.
Probiotics can cut bouts of infectious diarrhea by half a day to about 2 days.
The bacteria strains most likely to help are Lactobacilllus rhamnosus GG, Lactobacillus reuteri, and Saccharomyces boulardii. A mix of a few different probiotics may also help treat this type of diarrhea.
Antibiotics kill the bad germs in your body that make you sick, but they also kill the good bacteria. This can disrupt the normal balance in your intestines, leading to diarrhea. It’s common for 10% to 30% of people taking these medicines.
Studies of both children and adults have shown that probiotics taken before and with antibiotics can lower the risk of diarrhea. Saccharomyces boulardii and Lactobacillus GG seem to be the most effective.
Travelers often battle diarrhea caused by contaminated food or water. Up to 10% of people who get the condition while traveling end up with a case that lasts longer than 4 weeks.
Evidence is mixed on whether probiotics work for this condition. A 2007 report found that probiotics lowered the risk of getting travelers’ diarrhea. But other studies have shown that they don’t really help. The strongest evidence pointed to benefits from S. boulardii, Lactobacillus acidophilus, and Bifidobacteria bifidum.