Lactobacillus Rhamnosus

Image of yogurt, fruit and granola in a bowl on a table, which can contain the probiotic lactobacillus rhamnosus

What is Lactobacillus rhamnosus?

Lactobacillus rhamnosus GG is a form of naturally occurring bacteria that is commonly found in the genital and urinary tract of human females. It is one of the most widely used probiotic strains, and is often used to prevent or treat gastro-intestinal infections and diarrhea, and to stimulate immune responses that promote vaccination, or to prevent certain allergic reactions.[1]

L. rhamnosus is also considered one of the most extensively researched probiotics in the world, because over 400 studies have been published that establish its immune-modulating properties.[2]


Lactobacillus rhamnosus GG was originally isolated in 1985 in fecal samples of a healthy human adult by researchers Sherwood Gorbach and Barry Goldwin, which explains its typical surname letters GG.[1]

It was originally considered to be a subspecies of Lactobacillus casei, but was determined in later research to be a species of its own.[3]

L. rhamnosus was first identified as a potential probiotic strain because of its resistance to acid and bile, its growth characteristics, and its ability to adhere to the epithelial layer of the intestines.[1]

What are probiotics?

The term “probiotics” is used to describe live microorganisms that have a beneficial health effect on the person taking them.[4]

The concept of probiotics evolved from a theory first proposed in 1910 by Nobel Prize winning Russian scientist, Elie Metchnikoff. He theorized that the long life of Bulgarian peasants resulted from their consumption of fermented milk products.

He further promoted the belief that when beneficial bacteria are consumed, they positively influence the microflora of the colon by decreasing the toxic effects of other, non-beneficial colonic microflora.

This concept was developed further through the decades, and today, especially in Europe and Japan, probiotic-focused research is at an all-time high.[5,6]

Where is Lactobacillus rhamnosus found?

Like many lactose-based bacteria, lactobacillus rhamnosus can be naturally found in fermented products such as yogurt, kefir, and sour milk. It can also be grown outside the body, and can then be consumed orally in other products or in supplements for its medicinal benefit.[1]

What does Lactobacillus Rhamnosus do in the body?

Goldin and Gorbach, the original finders of L. rhamnosus, described it as unique in the “white, almost milky creamy colonies it would form, probably because of a polysaccharide in the cell wall.”

Because of the extensive research performed on the strain, it has been referred more recently to as the “Vitamin C of probiotics,” and is considered the most researched, safe, trusted, and effective immune-boosting probiotic in the world.[2]

Research has shown that Lactobacillus rhamnosus has numerous beneficial effects on inflammation and infection.

It blunts the amounts of inflammatory cytokines triggered by pathogenic bacteria, and as a result it reduces inflammation not only in the gastrointestinal tract but also in the lungs, liver, and blood. It reduces the invasive capacity of bacteria, and as a result, can be beneficial in the treatment of a number of inflammatory diseases and infections.[2]

Lactobacillus rhamnosus also seems to alter the immune response by limiting the ability of pathogens to release inflammatory molecules.

Some have theorized that it does this by quieting the gene NF-Kappa B, a key molecule that can lead to “inflammatory cascade” or runaway inflammation.

Some studies have suggested that L. rhamnosus may activate specific T-cells “Peyer’s patch), which may explain how taking this probiotic orally helps to protect against infection and inflammation as far away in the body as the ear, nose, skin, lungs, and urinary tract.[2]

Potential Health Benefits of Lactobacillus Rhamnosus?

The use of L. rhamnosus is common as a probiotic treatment to relieve or treat a number of disorders. Individual conditions for which evidence of L. rhamnosus’s possible effectiveness as a probiotic treatment exists are covered in the following sections.

Allergic Diseases

In studies published in The Lancet, L. rhamnosus has shown to be effective in preventing atopic diseases such as eczema, asthma and rhinoconjunctivitis in families with a hereditary history of such diseases.[7,8,9] In studies on milk-hypersensitive adults, L. rhamnosus was shown to reduce the immunoinflammatory response of this allergy by reducing the action of complement receptors CR1 and CR3.[10]

Diarrhea and Gastrointestinal Tract Disorders

L. rhamnosus is often employed as a probiotic to prevent and treat diarrhea and related gastrointestinal infections.

It has been shown to reduce the duration of periods of diarrhea, especially in children, and has also been found to lower the risk of developing gastrointestinal infections in hospitals when administered daily to children.[11]

In one study, treatment with L. rhamnosus reduced the risk of diarrhea associated with antibiotics from 22.4% to 12.3%.[12] L. rhamnosus also has been associated with lower rates of rotavirus gastroenteritis diarrhea in children who have been hospitalized.[13]

Weight Loss and Obesity

In one study, L. rhamnosus induced weight loss in women, reducing total fat mass and circulating leptin concentrations.[14] It has also shown anti-obesity and anti-inflammatory properties [15], and improved liver parameters in obese children with liver dysfunction noncompliant with lifestyle interventions.[16]

Irritable Bowel Syndrome (IBS)

L. rhamnosus is beneficial for patients with irritable bowel syndrome.[17] It has been found to reduce both the frequency and intensity of pain in children who have abdominal pain-related disorders, especially in the case of irritable bowel syndrome.[18]

Dental Health

L. rhamnosus lowers the oral count of Streptococcus mutans, the bacterium associated with caries (cavity) formation.[19] Also, one long-term study showed that consumption of milk supplemented with L. rhamnosus reduced the development of caries in children.[20]


L. rhamnosus activated humoral and cellular immune responses in mice.[21] L. rhamnosus beneficially regulated the balance between pro- and anti-inflammatory cytokines in the lungs.[22]

Respiratory Infections

Fermented milk supplemented with L. rhamnosus reduced the risk of respiratory tract infections that last longer than three days in children who have been hospitalized.[23]

Preterm infants who were treated with L. rhamnosus on a daily basis starting at age one week had a significantly lower incidence of respiratory episodes in the first 2 months.[24]

Consumption of L. rhamnosus also lowered the occurrence of respiratory problems in children attending day care centers[25], and children who received L. rhamnosus probiotics in another study had fewer days per month with respiratory symptoms than children in a control group.[26]

L. rhamnosus was found to offer a significant protection against ventilator-associated pneumonia among hospitalized patients.[27] And in patients with cystic fibrosis, long-term L. rhamnosus treatment decreased the number of pulmonary exacerbations and increased overall body weight.[28]

Urogenital Tract

L. rhamnosus GG and L. rhamnosus GR-1 appear to protect the urogenital tract by excreting biosurfactants to inhibit the adhesion of vaginal and urinary pathogens.[26]

Asperger Syndrome and ADHD

A 2015 study concluded that early probiotic supplementation may reduce the risk of neuropsychiatric disorder development later in childhood. Infants in the study received either L. rhamnosus or a placebo during their first six months and were then followed for 13 years.

At age 13, 17.1% of the children in the placebo group were diagnosed with Asperger syndrome or ADHD, while none of the children that received L. rhamnosus were diagnosed.[29]


A 2011 study reported that L. rhamnosus may have an effect on GABA neurotransmitter receptors, which have been causally associated with anxiety. Mice fed L. rhamnosus JB-1 had less anxiety and different levels of the brain-chemical sensor and stress hormones.[30]


In vitro studies in the laboratory have demonstrated that L. rhamnosus kills human cervical and colon adenocarcinoma cells.[31]

There are also preliminary findings that L. rhamnosus decreases the number of carcinogen-induced colon tumors and precancerous lesions in both animals and in human cells.[32], and that it shows antitumor effects in bladder cancer found in animals.[33]

Ways to Add More Lactobacillus Rhamnosus to Your Diet


Dairy products such as yogurt and kefir naturally contain Lactobacillus rhamnosus. But remember that due to modern pasteurization and manufacturing processes, the beneficial bacterial cultures don’t always survive.

Probiotic supplements

The most convenient way to add Lactobacillus salivarius to one’s diet is by taking probiotic supplements on a regular basis. Many studies have proven these supplements can be effective in maintaining good overall health.

However, it is always a good idea to read the label of products described as “probiotic” to make sure that Lactobacillus rhamnosus is, in fact, included in the mix of ingredients. Also make sure that the packaging of the product protects it from light and moisture, and that the package has an expiration date on its label. If it doesn’t, you should be suspicious and consider an alternative product.

Additional Recommendations on Choosing Your Probiotics

Probiotic strains included in the product

Because Lactobacillus rhamnosus is often not the only beneficial bacterium included in probiotic formulations, read up on the effects of other strains included in the product. These may include Lactobacillus acidophilus, Bifidobacterium bifidum, Bifidobacterium longum, Lactobacillus fermentum, and Lactobacillus salivarius.

Expiration date

Any probiotic supplement you consider should have an expiration date on its label. If it doesn’t, you should be suspicious and consider an alternative.

Also worth mentioning:
• Choose your supplements from a reputable company.
• Follow the directions on the label and take the recommended dosage.
• Avoid taking probiotics on an empty stomach.
• Store probiotics properly – in most cases that means in a cool, dry place.
• Probiotics work best when taken in addition to a healthy diet. Probiotics are able to flourish best when they’re combined with fruits, vegetables and foods rich in fiber.


Lactobacillus rhamnosus is considered safe for adults and children when taken in the recommended doses.

Taking with antibiotics

Taking antibiotics at the same time as Lactobacillus rhamnosus can reduce the probiotic’s effectiveness. To avoid this interaction, be sure to take your Lactobacillus rhamnosus supplements two hours before or after taking antibiotics.


There has been some preliminary research that indicates that probiotic bacteria might grow too well in people with weak or impaired immune systems. Although this has not happened with Lactobacillus rhamnosus in particular, if you have HIV/AIDS or are undergoing cancer treatment you should check with your physician before taking it.[34]

[expand title=”References“]

[6] Metchnikoff, E. (1908) Lactic acid bacteria as vaccines: The Prolongation of Life. Putmans Sons New York, NY.
[30] Science News, Belly bacteria boss the brain, August 29th, 2011

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