Lacticaseibacillus rhamnosus

Lacticaseibacillus rhamnosus (L. rhamnosus) is a type of probiotic ("good" bacteria) found in the mouth, vagina, and gut. It's also found in fermented foods.

"Good" bacteria such as L. rhamnosus can help break down food, absorb nutrients, and fight off "bad" organisms that might cause diseases. Specific strains of L. rhamnosus are commonly added to fermented foods like yogurt and are also found in probiotic supplements.

People use L. rhamnosus for diarrhea from antibiotics, eczema, preventing allergic reactions, and preventing respiratory tract infections. It is also used for hay fever, stomach pain, canker sores, colic, and many other conditions, but there is no good scientific evidence to support many of these other uses. There is also no good evidence to support using L. rhamnosus for COVID-19.

Don't confuse L. rhamnosus with other probiotics, or with fermented food products such as fermented milk, kefir, or yogurt. These are not the same. Also note that L. rhamnosus 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 rhamnosus rather than its new name, Lacticaseibacillus rhamnosus.