Skip to content
My WebMD Sign In, Sign Up
Font Size


Lactobacillus is a type of "friendly" bacteria. It lives in your body but doesn't cause disease. You can also get it in food and supplements.

Lactobacillus may help your body:

Recommended Related to Vitamins & Supplements


Quercetin is a plant pigment (flavonoid) that people sometimes take as a medicine. It is found in many plants and foods.

Read the Quercetin article > >

  • Break down food
  • Absorb nutrients
  • Resist infections in the gastrointestinal tract

Why do people take lactobacillus?

People take lactobacillus for many reasons.

Digestive system. People take lactobacillus to try to treat or prevent diarrhea. It can help children more quickly get over diarrhea caused by an infection.

Lactobacillus may also help prevent diarrhea for:

  • Travelers
  • Hospitalized adults
  • People taking antibiotics
  • Patients getting cancer treatment

People also take lactobacillus to try to treat other problems related to the digestive system. Studies show some promise for:

  • Colic in babies
  • Ulcerative colitis
  • Irritable bowel syndrome
  • Helicobacter pylori infection, which causes ulcers

There isn't enough research to know if lactobacillus helps with Crohn's disease or necrotizing enterocolitis (NEC) in premature babies.

Infections. Many studies show that lactobacillus may help prevent infections. For example, it may help prevent lung infections in children in daycare centers. It also may help treat or prevent vaginal infections caused by bacteria.

But there isn't enough known about using lactobacillus for colds or urinary tract infections. And it isn't clear if it can boost the immune system or prevent infections in people on ventilators.

Skin problems. People take lactobacillus to try to treat:

  • Fever blisters
  • Acne
  • Eczema
  • Canker sores
  • Hives

Eczema may benefit from the use of lactobacillus, but there isn't enough evidence to know if it helps with these other skin problems.

As for other uses, it's not clear whether it is effective for lactose intolerance, high cholesterol, or Lyme disease.

Researchers have used many different doses of lactobacillus. The optimal dose is not known. But a typical daily dose ranges from 1 to 10 billion living organisms. You take this divided into three to four doses each day. It may work better if the product is kept in the refrigerator.

Lactobacillus is called a probiotic when you take it in adequate amounts to help with health. However, supplement ingredients and quality may vary widely from maker to maker. This makes it hard to set a standard dose.

Can you get lactobacillus naturally from foods?

Lactobacillus is present in some fermented foods such as:

  • Yogurt
  • Cheese
  • Kefir
  • Sauerkraut
  • Olives
  • Pickles

It's also in milk and added to some infant foods.

What are the risks of taking lactobacillus?

Lactobacillus is likely safe for adults, children, and babies. Pregnant and breastfeeding women have also used one type of lactobacillus safely. But other types of lactobacillus need more study to be sure of its safety.

Side effects. Lactobacillus may cause mild gas or bloating.

Risks. Do you have a weakened immune system or short bowel syndrome? If so, talk to your doctor before taking lactobacillus. It may raise your risk of infections.

Interactions. Be cautious if you combine lactobacillus with medications that depress the immune system. You may be at higher risk of infection from the lactobacillus. Some examples of these medications are:

  • Cyclosporine
  • Prednisone
  • Corticosteroids

Take lactobacillus at least two hours before or after you take any antibiotics.

The FDA does not regulate supplements. Tell your doctor about any you're taking, even if they're natural. That way, your doctor can check on any potential side effects or interactions with medications or foods. He or she can let you know if the supplement might raise your risks.

WebMD Medical Reference

Reviewed by David Kiefer, MD on February 10, 2013

Vitamins and
Lifestyle Guide

Which Nutrients
Are You Missing?

Learn More

Today on WebMD

Woman taking a vitamin or supplement
Man taking a vitamin or supplement
Woman in sun
Flaxseed added fiber
Woman sleeping
Woman staring into space with coffee
Related Newsletters

Stay Informed with the latest must-read information delivered right to your inbox.