Probiotics are live bacteria and yeasts that are good for your health, especially your digestive system. We usually think of these as germs that cause diseases. But your body is full of bacteria, both good and bad. Probiotics are often called “good” or “helpful” bacteria because they help keep your gut healthy.

How Do They Work?

Researchers are trying to figure out exactly how probiotics work. Some of the ways they may keep you healthy:

• When you lose “good” bacteria in your body, for example after you take antibiotics, probiotics can help replace them.
• They can help balance your “good” and “bad” bacteria to keep your body working the way it should.

Types of Probiotics

Many types of bacteria are classified as probiotics. They all have different benefits, but most come from two groups. Ask your doctor about which might best help you.

Lactobacillus. This may be the most common probiotic. It’s the one you’ll find in yogurt and other fermented foods. Different strains can help with diarrhea and may help with people who can’t digest lactose, the sugar in milk.

Bifidobacterium. You can also find it in some dairy products. It may help ease the symptoms of irritable bowel syndrome (IBS) and some other conditions.

Saccharomyces boulardii  is a yeast found in probiotics. It appears to help fight diarrhea and other digestive problems.