It’s easy to view bacteria and yeasts through a particular lens, without realizing that these microorganisms serve various functions. Certainly, bacteria can lead to infections, but certain bacteria also are important for maintaining health.

Probiotics are live microorganisms (mostly bacteria and some yeasts) that may offer various health benefits. Probiotics are sometimes referred to as “good” or “beneficial” microbes due to their role in balancing the gut ecosystem. The Mayo Clinic reports that research suggests probiotics may be helpful, but it hasn’t yet been proven that probiotics improve health and are safe for everyone. While side effects from probiotic supplements seem to be rare, it’s best to consult a physician before taking such products.

The National Center for Complementary and Integrative Health says the most common probiotics are bacteria that belong to groups called Lacobacillus and Bifidobacterium. Others are yeasts such as Saccharomyces boulardii. Probiotics are found in various foods, including fermented dairy products like yogurt, kefir and cheese as well as other fermented foods, including sauerkraut, kimchi, pickles, tempeh, miso, sourdough, salami, olives, and kombucha. Additional forms of probiotics include probiotic capsules and powders.

The terms prebiotics and probiotics cannot be used interchangeably. Harvard Health says prebiotics are ingredients in certain foods that the intestines cannot fully digest. One can think of prebiotics as the food upon which probiotics feed. Prebiotics also may trigger the growth of good microbes in the digestive tract.

Probiotics may benefit health through several mechanisms. They may restore gut microbe balance after a poor diet, illness or antibiotic use. Probiotics can help crowd out harmful pathogens in the gut. They may reduce “leaky gut” by supporting gut barrier integrity. Probiotics also may calm inflammation and help boost the immune system.

Probiotics are largely known for their use in the digestive tract, but probiotics also come in topical versions or suppositories to target specific areas. However, caution should be heeded and any new products should be discussed with a doctor.