Reuterina Acute is a probiotic containing Lactobacillus reuteri, used mainly for acute diarrhoea — particularly in children, and after a course of antibiotics. It is one of the few probiotic strains with genuine trial evidence behind it, and it works for a narrower set of things than probiotics are generally sold for.
What is Reuterina Acute?
Reuterina Acute is a health supplement, not a registered medicine, and it does not appear on the South African Medicine Price Registry — which lists SAHPRA-approved medicines. Supplements are regulated far more lightly.
The Reuterina range is built on ***Limosilactobacillus reuteri* DSM 17938** — formerly called Lactobacillus reuteri. Check your own pack for the strain, the dose in colony-forming units (CFU), and any additional ingredients, since formulations differ and the “Acute” version typically carries a higher dose than the everyday one.
Strain matters more than almost anything else about a probiotic. “Probiotic” is a category covering hundreds of strains with completely different effects, and evidence for one says nothing about another, even within a species. DSM 17938 is one of the few properly trialled.
How it works. L. reuteri colonises the gut temporarily, competes with harmful bacteria, produces reuterin — an antimicrobial that inhibits several gut pathogens — and appears to modulate local immunity and gut motility.
It does not permanently colonise. Probiotics are transient — they pass through, and the effect stops within days of stopping the supplement. This is why they are taken as short courses for specific situations rather than indefinitely.
“Acute” indicates the higher-dose format intended for an active episode rather than daily maintenance.
If you search the medicine register for “acute”, you will get dialysis acid concentrate — an industrial solution used in haemodialysis machines. That is a letters-match, nothing to do with this product. Disregard it.
What is Reuterina Acute commonly used for?
Where the evidence is genuinely good:
- Acute infectious diarrhoea in children — the best-supported use. Trials show DSM 17938 shortens acute gastroenteritis by roughly a day. A day matters when you have a sick child.
- Antibiotic-associated diarrhoea, where a probiotic alongside the course reduces the chance of it. Start it with the antibiotic, not after.
- Infant colic in breastfed babies, where L. reuteri has the most evidence — several trials show reduced crying time, though results in formula-fed babies are less consistent.
Where it is used with weaker support:
- Traveller’s diarrhoea, for prevention and treatment.
- Functional abdominal pain and constipation in children, and infant regurgitation.
- Irritable bowel syndrome, where probiotics show modest benefit but the best strain is unsettled.
- General “gut health” and immune support, which is marketing rather than evidence.
Two things it does not replace.
In acute diarrhoea, rehydration is the treatment. Oral rehydration solution prevents the dehydration that actually causes harm. A probiotic may shorten the illness by a day; rehydration is what keeps a child safe. Get the ORS first.
It does not treat the cause of an infection. Bacterial dysentery, parasites and C. difficile need proper diagnosis and treatment.
Who commonly looks for Reuterina Acute and why
Parents of a child with gastroenteritis, usually recommended by a pharmacist or clinic — by far the largest group.
Parents of a colicky baby, often after weeks of broken sleep. Worth saying plainly: colic is distressing, common, and self-limiting, and it is not caused by anything a parent has done wrong. L. reuteri is one of the few things with trial support, and it is worth trying in a breastfed baby — but the exhaustion is real and support matters as much as the drops.
People starting a course of antibiotics, hoping to avoid the diarrhoea.
Travellers packing it prophylactically, and adults with IBS looking for something to try.
People who have read about the microbiome and want a general gut supplement. This is the group least likely to benefit — probiotics work best for specific problems in specific situations, not as a daily tonic. Eating more fibre and fermented foods does more for a healthy microbiome than any capsule.
What to check on the label before taking Reuterina Acute
- The exact strain, including the designation — L. reuteri DSM 17938. A different strain has different evidence.
- The CFU count per dose. This is the potency figure. The “Acute” format is usually higher-dose.
- The expiry date, which matters more here than with most supplements — live bacteria die off, and an out-of-date product may contain far fewer than stated.
- Storage requirements. Follow the pack, since heat kills the organisms.
- Additional ingredients, particularly with a dairy allergy or lactose intolerance.
Safety, interactions and when to seek professional advice
For most healthy people, probiotics are very safe. Mild bloating and wind in the first few days are the usual complaints, and they settle.
There is one situation where they are genuinely not safe, and it is important:
Do not take probiotics without medical advice if you have a seriously weakened immune system — advanced HIV with a low CD4 count, active chemotherapy, after an organ transplant, on high-dose immunosuppressants, or if you have a central venous line or short bowel syndrome. Rare but serious infections with the probiotic organism itself have occurred in these groups.
Also speak to a doctor or pharmacist first if:
- The person is a premature or very young infant.
- There is a heart valve abnormality or prosthetic valve.
- There is severe acute pancreatitis, where probiotics have been associated with harm.
- You are pregnant — generally considered fine, but confirm the specific product.
Space it a couple of hours from an antibiotic dose, so the antibiotic does not simply kill the organisms as they arrive. Take the probiotic through the whole antibiotic course and for a week or two afterwards.
See a doctor rather than self-treating if:
- A child under six months has diarrhoea, or a child of any age has signs of dehydration — dry mouth, no tears, sunken eyes, few wet nappies, drowsiness or unusual floppiness. Get medical help urgently.
- Diarrhoea contains blood or mucus, or comes with high fever.
- Diarrhoea lasts more than two days in a child or more than a week in an adult.
- There is severe abdominal pain, or persistent vomiting preventing fluids.
- Diarrhoea follows recent antibiotics and is severe, watery or bloody — this may be C. difficile and needs treatment, not a probiotic alone.
- There is unintentional weight loss, ongoing change in bowel habit, or diarrhoea waking you at night.
- A baby’s crying is inconsolable, unusual, or accompanied by fever, vomiting, poor feeding, or a rash that does not fade under pressure. Colic is a diagnosis of exclusion.
Rehydration first, always. Oral rehydration solution is the single most important treatment in acute diarrhoea, is available cheaply from any pharmacy and free at clinics, and prevents the complication that actually causes harm.
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Frequently asked questions
What is Reuterina Acute used for? Mainly acute diarrhoea, particularly in children, and diarrhoea associated with antibiotics. It contains the probiotic Lactobacillus reuteri.
Does it actually work? For acute gastroenteritis in children, yes — trials show it shortens the illness by roughly a day. For antibiotic-associated diarrhoea and infant colic in breastfed babies, the evidence is also reasonable. For general “gut health”, much less so.
Is it a substitute for rehydration? No. Oral rehydration solution is the treatment in acute diarrhoea. A probiotic may shorten the illness; rehydration is what prevents harm.
When should I take it with antibiotics? Start it with the antibiotic, take it through the course and for a week or two after, and space each dose a couple of hours from the antibiotic.
How long does the effect last? Only while you take it. Probiotics pass through rather than permanently colonising, and the effect fades within days of stopping.
Does the strain matter? Enormously. Evidence for one strain says nothing about another. Check for L. reuteri DSM 17938 on the pack.
Can anyone take it? Almost everyone, but not people with a seriously weakened immune system, a central venous line or short bowel syndrome without medical advice.
Can I give it to a baby? L. reuteri is used in infants for colic, with reasonable evidence in breastfed babies. Check the format and dose, and speak to a clinic for a very young or premature infant.