Limosilactobacillus reuteri
Limosilactobacillus reuteri


Limosilactobacillus reuteri (L. reuteri) is a type of probiotic ("good" bacteria) normally found in the digestive tract. It produces lactic acid in the gut.

"Good" bacteria such as L. reuteri can help break down food, absorb nutrients, and fight off "bad" organisms that might cause diseases. L. reuteri is sometimes added to fermented foods like yogurt and is also found in probiotic supplements.

People use L. reuteri for stomach pain, colic, constipation, diarrhea, Helicobacter pylori (H. pylori) infection, and high cholesterol. It is also used for eczema, canker sores, diabetes, and many other conditions, but there is no good scientific evidence to support most of these other uses. There is also no good evidence to support using L. reuteri for COVID-19.

Don't confuse L. reuteri with other probiotics, or with fermented food products such as fermented milk, kefir, or yogurt. These are not the same. Also note that L. reuteri used to be classified under the Lactobacillus genus. But Lactobacillus was split up into 25 different genera in April 2020. Some product labels might still list this species as Lactobacillus reuteri rather than its new name, Limosilactobacillus reuteri.
When taken by mouth: L. reuteri is likely safe. It's been used safely alone and together with other probiotics for up to 6 months. Some people might experience diarrhea or constipation, but it's usually well-tolerated.

Special Precautions & Warnings:

Pregnancy and breast-feeding: L. reuteri is possibly safe when taken by mouth appropriately while pregnant and breast-feeding.

Children: L. reuteri is likely safe when taken by mouth in children. It's been used safely for up to 4 weeks in infants and up to 12 weeks in older children.

Weakened immune system: L. reuteri has caused blood infections in a small number of people with weakened immune systems. If you have a weakened immune system, talk with your healthcare provider before taking L. reuteri.

Damaged heart valves: L. reuteri can cause an infection in the inner lining of the heart chambers and heart valve. This is extremely rare, but people with damaged heart valves should stop taking probiotics before dental procedures or surgical procedures.


NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
Likely effective Effectiveness definitions
Possibly effective Effectiveness definitions
  • Stomach pain. Taking L. reuteri by mouth seems to reduce stomach pain in children. It's not clear if it helps adults.
  • Excessive crying in infants (colic). Giving infants L. reuteri by mouth seems to help with colic.
  • Constipation. Taking L. reuteri by mouth seems to reduce constipation.
  • Diarrhea. Taking L. reuteri by mouth slightly reduces how long diarrhea lasts in children.
  • A digestive tract infection that can lead to ulcers (Helicobacter pylori or H. pylori). Taking L. reuteri by mouth along with most standard drug therapies used to treat H. pylori seems to reduce the side effects from these drugs. But it's not clear if L. reuteri helps treat H. pylori infection.
  • High cholesterol. Taking L. reuteri by mouth seems to help lower cholesterol levels by a small amount.
There is interest in using L. reuteri for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
Likely ineffective Effectiveness definitions
Possibly ineffective Effectiveness definitions
Insufficient evidence Effectiveness definitions

Dosing & administration

L. reuteri is sometimes added to fermented foods such as yogurts. It's commonly taken in dietary supplements.

In adults, L. reuteri has most often been taken by mouth, alone or together with other probiotics, in doses of 200 million to 50 billion colony-forming units (CFUs) daily, for up to 6 months. In children, L. reuteri has most often been taken by mouth in doses of 100 million to 20 billion CFUs daily, for up to 6 months. Speak with a healthcare provider to find out what dose might be best for a specific condition.

Interactions with pharmaceuticals

Antibiotic drugs

Interaction Rating=Moderate Be cautious with this combination.

L. reuteri is a type of friendly bacteria. Antibiotics are used to reduce harmful bacteria in the body. Taking antibiotics along with L. reuteri can reduce the effects of L. reuteri. To avoid this interaction, take L. reuteri products at least 2 hours before or after antibiotics.

Interactions with herbs & supplements

There are no known interactions with herbs and supplements.

Interactions with foods

There are no known interactions with foods.
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This monograph was last reviewed on 22/02/2023 11:00:00 and last updated on 10/06/2022 09:21:46. Monographs are reviewed and/or updated multiple times per month and at least once per year.
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