Skip to main contentLink to External Link Policy
Información en Español
National Center for Complementary and Integrative Health

5 Things To Know About Probiotics

Probiotics are live microorganisms (e.g., bacteria) that are either the same as or similar to microorganisms found naturally in the human body and may be beneficial to health. If you picture the human body as a “host” for bacteria and other microorganisms, you might have a better understanding of probiotics. The body, especially the lower gastrointestinal tract (the gut), contains a complex and diverse community of bacteria. Although we tend to think of bacteria as harmful “germs,” many bacteria actually help the body function properly.

Probiotics are available to consumers in oral products such as dietary supplements and yogurts, as well as other products such as suppositories and creams. It is important to be aware that the U.S. Food and Drug Administration (FDA) has not approved any health claims for probiotics. In 2023, the FDA warned health care providers that premature infants who are given probiotics are at risk of severe, potentially fatal infections caused by the microorganisms in the products. Here are some other things you should know:

  1. There is some evidence that probiotics may be helpful for acute diarrhea, antibiotic-associated diarrhea, and atopic eczema (a skin condition most commonly seen in infants).

  2. Although some probiotic formulations have shown promise in research, strong scientific evidence to support other uses of probiotics for most conditions is lacking.

  3. Studies suggest that probiotics usually have few side effects. However, the data on safety, particularly long-term safety, are limited, and the risk of serious side effects may be greater in people who have underlying health conditions. Cases of severe or fatal infections have been reported in premature infants who were given probiotics.

  4. Probiotic products may contain different types of probiotic bacteria and have different effects in the human body. The effects also may vary from person to person.

  5. If you are considering a probiotic dietary supplement, talk with your health care provider first. Do not replace scientifically proven treatments with unproven products or practices.