Probiotics are live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut. They are also called “friendly bacteria” or “good bacteria.” Probiotics are available to consumers mainly in the form of dietary supplements and foods. They can be used as complementary and alternative medicine (CAM).1 To find out more about topics and resources mentioned in this fact sheet, see “For More Information.”
Key Points
• People use probiotic products as CAM to prevent and treat certain illnesses and support general wellness.
• There is limited evidence supporting some uses of probiotics. Much more scientific knowledge is needed about probiotics, including about their safety and appropriate use.
• Effects found from one species or strain of probiotics do not necessarily hold true for others, or even for different preparations of the same species or strain.
• Tell your health care providers about any CAM practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care. For tips for talking with your health care providers about CAM, see NCCAM’s Time to Talk campaign at nccam.nih.gov/timetotalk/.
What Probiotics Are
Experts have debated how to define probiotics. One widely used definition, developed by the World Health Organization and the Food and Agriculture Organization of the United Nations, is that probiotics are “live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host.” (Microorganisms are tiny living organisms—such as bacteria, viruses, and yeasts—that can be seen only under a microscope.)
1
CAM is a group of diverse medical and health care systems, practices, and products that are not presently considered to be part of conventional medicine. Complementary medicine is used together with conventional medicine, and alternative medicine is used in