LGG Probiotic Drops for Infants and Children

LGG probiotic drops deliver Lactobacillus rhamnosus GG, a single, well-characterised bacterial strain, in a liquid form suited to infants and young children. LGG has been studied in children for acute diarrhoea, antibiotic-associated diarrhoea, functional abdominal pain and cow's milk allergy. Evidence ranges from moderate to limited depending on the use, and results apply to this specific strain.

This guide explains what LGG is, how it interacts with the child's gut, how strong the evidence is for each paediatric use, and what parents and paediatricians should consider before giving drops.

How does a child's gut microbiome change from birth to school age?

The gut microbiome, the community of bacteria, fungi and viruses living in the intestine, changes faster in the first three years of life than at any later stage. Its development shapes digestion, immune training and resistance to infection.

At birth, mode of delivery sets the first pattern. Vaginally born babies acquire bacteria from the mother's birth canal and gut, while babies born by caesarean section are first colonised mainly by skin and hospital bacteria. Breastfed infants then develop a community dominated by Bifidobacterium species, which feed on human milk oligosaccharides, complex sugars in breast milk that the baby cannot digest.

The introduction of solid food around six months brings the largest single shift. Fibre-fermenting bacteria such as Bacteroides and members of the Lachnospiraceae family expand, and production of short-chain fatty acids, including butyrate, rises. By about three years, the microbiome resembles an adult pattern, though it continues to mature through childhood.

Antibiotics interrupt this sequence. A single course can sharply reduce microbial diversity, and repeated courses in early childhood are associated with altered microbiome development. This is one context in which paediatric probiotic research has concentrated.

What is Lactobacillus rhamnosus GG?

Lactobacillus rhamnosus GG is a lactic acid bacterium first isolated from the intestine of a healthy adult in the 1980s at Tufts University in Boston. Its current scientific name is Lacticaseibacillus rhamnosus GG (formerly Lactobacillus rhamnosus GG), following the 2020 genomic reclassification of the lactobacilli. Most labels and clinical papers still use LGG.

The strain is deposited in the American Type Culture Collection under the code ATCC 53103. That code allows any laboratory to obtain the reference strain and confirm that a product contains the organism studied in clinical trials. The history of how LGG came to be so widely researched is covered in ELMED's article on what makes LGG the world's most researched probiotic strain.

LGG survives exposure to stomach acid and bile reasonably well, attaches to the mucus layer lining the intestine, and persists in the gut for days to a few weeks after supplementation stops. It does not settle permanently.

What happens to LGG after a child swallows it?

After ingestion, LGG passes through the stomach, where acid kills a proportion of cells, and then through the small intestine, where bile salts add further stress. LGG tolerates both better than many lactobacilli, so a meaningful fraction reaches the lower intestine alive.

In the gut, LGG attaches to mucus and multiplies for a period. Studies that tracked the strain in stool samples typically detected it during supplementation and for one to three weeks afterwards, after which levels fell below detection in most children. A minority of people retain it for longer, but permanent colonisation is uncommon.

One metabolic detail distinguishes LGG from many related strains. LGG does not ferment lactose, the main sugar in milk, so it does not depend on dairy for growth. This is one reason it suits non-dairy carriers such as oil-based or water-based drops.

How does LGG work in a child's gut?

Several mechanisms behind LGG's effects have been identified at the molecular level, which is unusual for a probiotic. The main ones are adhesion to intestinal mucus, secretion of proteins that protect the gut lining, and signalling to the immune system.

Adhesion through pili

LGG carries hair-like surface structures called SpaCBA pili. The tip protein, SpaC, binds human intestinal mucus. This adhesion helps LGG stay in the gut longer than many other lactobacilli and brings it close to the cells it signals to. Strains of L. rhamnosus that lack these pili attach far less well, which is one concrete reason why strain identity matters.

Protection of the gut barrier

LGG secretes two proteins, known as p40 and p75, that act on intestinal epithelial cells, the single layer of cells lining the gut. In laboratory and animal studies, these proteins activate the epidermal growth factor receptor on those cells, which helps preserve tight junctions, the protein seals between neighbouring cells. Intact tight junctions limit the passage of toxins and microbes from the gut into the tissue beneath.

Immune signalling

Components of the LGG cell wall, including lipoteichoic acid, interact with immune receptors in the gut lining. In experimental models, LGG increases secretory IgA, the antibody class that coats the gut surface, and shifts immune signalling away from inflammation. How much of this occurs in a healthy child taking drops is not precisely known.

Competition with pathogens

Like other lactobacilli, LGG produces lactic acid, lowering local pH, and competes with harmful bacteria for attachment sites and nutrients. In cell culture, it inhibits adhesion of some diarrhoea-causing organisms.

What does the evidence show for acute diarrhoea in children?

The evidence for LGG in acute gastroenteritis, an infection of the gut causing sudden diarrhoea and often vomiting, is mixed and currently rated as low certainty. Earlier trials suggested shorter illness, while two large trials published in 2018 found no clear benefit in children treated in emergency departments.

In its 2020 recommendations, ESPGHAN, the European Society for Paediatric Gastroenterology, Hepatology and Nutrition, listed LGG among the probiotics that may be considered alongside oral rehydration, with a weak recommendation. This was a downgrade from a stronger earlier position. A separate article examines what ESPGHAN says about LGG for acute diarrhoea in detail, and practical rehydration is covered in probiotic drops with ORS and zinc.

Oral rehydration solution is the treatment that prevents dehydration. A probiotic is at most an addition.

Can LGG help prevent antibiotic-associated diarrhoea in children?

LGG has moderate-quality evidence for reducing antibiotic-associated diarrhoea in children. Antibiotics disturb the gut microbiome, and loose stools during or shortly after a course are common, especially with broad-spectrum antibiotics such as amoxicillin with clavulanate.

ESPGHAN's working group on probiotics has recommended LGG or Saccharomyces boulardii when a probiotic is used to prevent antibiotic-associated diarrhoea in children with risk factors, such as young age, broad-spectrum antibiotics or a previous episode. The doses used in trials varied, and the paediatrician sets the dose for any individual child. ELMED's article on antibiotic-associated diarrhoea across age groups explains causes and risk factors.

Does LGG help with functional abdominal pain?

LGG has limited but consistent evidence in children with irritable bowel syndrome, a functional gut disorder causing recurrent abdominal pain with changes in stool pattern. Randomised trials in school-age children, notably from Poland and Italy, reported fewer and less intense pain episodes with LGG than with placebo over several weeks.

The effect appeared mainly in children with irritable bowel syndrome rather than in those with pain that has no bowel pattern change. These are older children, typically given LGG as capsules or sachets rather than infant drops. Recurrent abdominal pain in any child needs medical assessment first, since conditions such as coeliac disease, constipation and urinary infection can present the same way.

What is the evidence for LGG in cow's milk protein allergy?

Cow's milk protein allergy is an immune reaction to proteins in cow's milk, usually appearing in the first months of life. Most children outgrow it, and research has asked whether LGG can speed that process.

A research group in Naples, Italy, conducted several trials in which infants with cow's milk allergy received an extensively hydrolysed casein formula with added LGG. These infants developed tolerance to cow's milk sooner than infants given the same formula without LGG or other formula types. The findings are promising, but they come largely from one research centre and involve LGG within a specific formula, not drops. The detail is discussed in LGG and cow's milk protein allergy.

Does LGG prevent infections or eczema?

Evidence that LGG prevents respiratory infections or allergic eczema is limited and inconsistent. A trial in Croatian daycare centres found fewer upper respiratory infections in children given LGG in fermented milk. A hospital-based trial from the same group reported fewer gut and respiratory infections acquired in hospital.

For eczema, a landmark Finnish trial published in The Lancet in 2001 gave LGG to mothers before birth and to their high-risk infants afterwards, and reported about half as much early eczema in the LGG group. A later German trial using a similar approach did not reproduce this result. Current allergy guidelines do not recommend LGG specifically for eczema prevention.

How does LGG compare with other probiotics used in children?

Several probiotics other than LGG have paediatric evidence, and each has a different profile. Comparisons are useful only at the level of strains, because the organisms differ in biology and in the conditions they were tested for.

Saccharomyces boulardii CNCM I-745. A probiotic yeast rather than a bacterium. Antibiotics do not kill it, which makes it a common alternative to LGG for antibiotic-associated diarrhoea. ESPGHAN has given it a comparable recommendation for that use.

Limosilactobacillus reuteri DSM 17938. Studied mainly for infant colic in breastfed babies and for acute diarrhoea, with weak recommendations from ESPGHAN.

Bacillus clausii. A spore-forming bacterium widely used in India. Its spores resist stomach acid, and clinical evidence in children is less extensive than for LGG.

Bifidobacterium combinations. Certain multi-strain products have been studied in preterm infants and for eczema, with variable results.

No probiotic has been shown to be superior to all others for every childhood condition. The choice depends on the problem, the age of the child and the evidence for the specific strain.

Why does the strain matter for LGG?

Probiotic effects are properties of individual strains. The species Lacticaseibacillus rhamnosus includes many strains with different genes, and only some share LGG's pili, secreted proteins and clinical record.

The designation ATCC 53103 on a label confirms the product uses the LGG strain itself. A product listing only "Lactobacillus rhamnosus" without a strain code cannot claim LGG's evidence. Even with the correct strain, results depend on dose, viability through shelf life and the condition being studied.

What is in Rhambac GG Drops?

Rhambac® GG Drops from ELMED Life Sciences contain Lactobacillus rhamnosus GG ATCC 53103, the reference LGG strain, at 1 billion CFU per 6 drops. ELMED describes the drop format as suitable for all ages, and the product carries a shelf life of 24 months.

CFU, or colony forming units, counts the live bacterial cells able to grow on a laboratory plate. The figure describes quantity, not effect. For older children and adults who prefer capsules, ELMED also offers Rhambac® GG Capsules.

Rhambac GG Drops are a nutraceutical product. A paediatrician can advise whether LGG suits a particular child, at what dose and for how long.

When might a paediatrician suggest LGG drops?

A paediatrician may suggest LGG drops in a few defined situations, each backed by a different level of evidence:

• during a course of broad-spectrum antibiotics in a child with risk factors for antibiotic-associated diarrhoea
• alongside oral rehydration in a well child with acute gastroenteritis, when the family wishes to try a probiotic
• for a school-age child with irritable bowel syndrome, as one part of a wider plan
• in an infant with cow's milk protein allergy, after discussion with an allergist

Each use has a natural end point. A course tied to antibiotics ends shortly after the antibiotics do. A course for acute diarrhoea lasts days, not months. Ongoing use for functional symptoms should be reviewed after a defined trial period, typically four to eight weeks, with the child's symptom record used to decide whether to continue.

Situations without supporting evidence include routine daily use in healthy children, use specifically because of caesarean birth, and attempts to improve appetite or weight.

How are LGG drops given to infants and children?

LGG drops are given by mouth, usually once a day, either directly from a spoon, onto the nipple before a feed, or mixed into a small amount of room-temperature milk, water (for children over six months) or soft food. The number of drops and the duration should follow the label and the paediatrician.

Practical points that protect the live bacteria:

Avoid heat. Hot milk, tea or freshly cooked food kills probiotic bacteria. Add drops only to cool or room-temperature food.

Shake before use. Bacteria settle in the bottle between doses.

Count upright. Hold the bottle vertically so drops are a consistent size.

Space from antibiotics. If the child is on an antibiotic, giving LGG two to three hours away from each antibiotic dose limits direct killing of the probiotic.

Store as labelled. Keep the bottle away from sunlight and kitchen heat, and note the opening date.

Is LGG safe for infants and children?

LGG has an extensive safety record in healthy children, with millions of doses consumed worldwide and adverse event rates in trials similar to placebo. The main concern is rare bloodstream infection in children with specific vulnerabilities.

Parents should not start LGG without medical advice if the child:

• was born preterm and is still in, or recently left, neonatal care
• has a weakened immune system from illness or medication
• has a central venous catheter
• has short bowel syndrome or recent gut surgery
• is critically ill or in intensive care

Short-term wind or a change in stool pattern sometimes appears in the first days. Is LGG safe for newborns and infants? explains the safety data in detail, and probiotics and preterm babies covers why neonatal units handle probiotics under strict protocols.

When does a child need a doctor rather than a probiotic?

Diarrhoea, abdominal pain or feeding problems need prompt medical review in several situations. These include signs of dehydration (fewer wet nappies, dry mouth, no tears, sunken eyes, unusual drowsiness), blood in the stool, high or persistent fever, repeated vomiting that prevents drinking, severe or worsening abdominal pain, and diarrhoea lasting more than a week. In infants under three months, any fever of 38°C or more is urgent.

What can LGG not do?

LGG does not replace oral rehydration in diarrhoea, does not treat bacterial infections that need antibiotics, and does not correct poor weight gain, which always requires medical investigation. It has not been shown to improve general immunity in healthy children with no specific problem, to raise appetite, or to change long-term growth.

Constipation is another condition where LGG has not helped. Trials testing it for childhood constipation found no clear benefit over standard care with laxatives and dietary changes. Children with hard stools, pain on passing them or infrequent bowel movements need assessment and conventional treatment.

How can parents judge the quality of an LGG product?

A good-quality LGG product names the strain code ATCC 53103, guarantees the CFU count until expiry rather than only at manufacture, gives clear storage instructions, and is produced by a GMP Certified manufacturer. Parents should also check the carrier liquid and any added ingredients if the child has known allergies.

Key takeaways

• LGG (Lacticaseibacillus rhamnosus GG, ATCC 53103) is among the most studied probiotic strains in children, with mechanisms identified at the molecular level.
• Evidence is moderate for preventing antibiotic-associated diarrhoea, low certainty for treating acute gastroenteritis, and limited for irritable bowel syndrome and cow's milk allergy.
• Oral rehydration solution remains the essential treatment for diarrhoea; LGG is an optional addition.
• Rhambac® GG Drops contain LGG ATCC 53103 at 1 billion CFU per 6 drops, and a paediatrician should guide dose and duration.
• Preterm, immunocompromised or critically ill children need medical supervision before any probiotic.