Can probiotics help against diarrhea?

Photo of a woman eating yoghurt (PantherMedia / imagepointfr) Probiotics can make diarrhea go away about one day faster. Generally speaking, probiotic products – which mostly contain certain lactic acid bacteria – are well tolerated.

Diarrhea is often caused by an intestinal (bowel) infection. As long as diarrhea isn’t severe, it is usually enough to simply drink plenty of fluids to avoid dehydration, and wait for the infection to run its course. However, in small children and older people the loss of fluid can quickly become so dangerous that special treatment is needed. Life-threatening cases of diarrhea are rare in industrialized countries, though.

In mild cases, people are sometimes advised to eat probiotic foods in addition to drinking a lot of fluids. Probiotic products have special microorganisms like bacteria or yeast in them. These are thought to reach the bowel, where they suppress the germs that are causing the diarrhea and help the body fight them. The best known probiotics are lactic acid bacteria (lactobacilli). They are found in natural yogurt and other dairy products, as well as in some dietary supplements.

Research on the effects of probiotics

To find out how well probiotics help against acute diarrhea, researchers from the Cochrane Collaboration analyzed relevant studies in this area. They found 63 studies looking at the effectiveness of probiotics for acute diarrhea. Just overAbout 8,000 people took part in these studies.

Most of the participants were children whose diarrhea lasted less than two weeks. They took probiotics in various forms, such as yogurts, milk, special infant formula, as a powder or in capsules.

Probiotics can make diarrhea go away faster

The research showed that probiotics help: They shortened the illness by one day on average. In some studies, researchers counted how many of the people had no more diarrhea after three days:

  • Without treatment: About 34 out of 100 people who didn’t take probiotics were diarrhea-free after three days.
  • With treatment: About 55 out of 100 people who took probiotics were diarrhea-free after three days.

In other words, probiotics made the diarrhea go away faster in 21 out of 100 people.

But it isn’t clear whether some probiotic foods and products are more effective than others. So there may be differences between yogurt, capsules and powder, or between lactic acid bacteria and other microorganisms.

Side effects

There were hardly any reports of side effects in these studies. Overall, the probiotic products were well tolerated. But there’s a chance that the bacteria or yeast in probiotics may sometimes cause infections themselves in people who have a very weak immune system or particular serious illnesses.