Gastroenteritis is a common infection of the digestive tract, causing vomiting, diarrhoea and discomfort. Its management can be supported through nutrition and probiotics. This article explores the role of dietary strategies and gut microbiome interventions in easing symptoms and promoting recovery.
Gastroenteritis, also known as stomach flu or food poisoning, is an intestinal tract infection caused by viruses or bacteria. The most common viral causes are norovirus and rotavirus, while common bacterial causes include Escherichia coli, Salmonella and Campylobacter1. When these pathogens reach the gut, they inflame the mucosal lining of the intestinal tract and disrupt the gut microbiome. Common symptoms include nausea, vomiting, diarrhoea and abdominal pain2. Gastroenteritis is a significant public health issue, affecting around 1 in 5 people in the UK each year3.
Vomiting after eating is very common during gastroenteritis due to a heightened gut–brain response. Eating or drinking increases pressure on the irritated stomach lining, which sends signals to the brain. This halts digestion and delays gastric emptying. As a result, food and liquid remain in the stomach, increasing pressure and irritation. Eventually, the brain coordinates muscular contractions in the gut, leading to vomiting to remove the source of irritation4.
Continuous vomiting can lead to dehydration, electrolyte imbalance and altered acid–base balance5. If vomiting persists beyond the typical 2–7 day duration, medical advice should be sought6.
Gastroenteritis can be very uncomfortable. Oral rehydration and electrolyte replacement are the primary treatments, alongside gradual reintroduction of easily digestible foods7. Intake should move from clear liquids to bland foods as the stomach becomes more tolerant of solids8.
If symptoms persist longer than a week, intravenous rehydration may be required to bypass the stomach and restore fluid balance. This is particularly important for high-risk groups such as frail individuals, those who are malnourished, or very young or elderly patients7.
After vomiting, it is important to allow the stomach time to recover before reintroducing food. A rest period of 30–60 minutes is recommended before taking small sips of clear fluids such as water or oral rehydration solutions. Large volumes may trigger further vomiting9.
Once food is tolerated, plain, starchy options such as white rice, toast or potatoes are typically well tolerated and gentle on the digestive tract.
Because gastroenteritis disrupts the gut microbiome, lactose in dairy products may be harder to digest and can worsen symptoms10. Fatty and spicy foods may also irritate the gut and should be avoided for at least 48 hours to allow recovery11.
Both viral and bacterial gastroenteritis can lead to acute dysbiosis, which is an imbalance between beneficial and harmful gut bacteria. A healthy gut microbiome produces protective factors that help prevent gastrointestinal infections12. During dysbiosis, harmful bacteria can dominate, leading to inflammation and increased gut sensitivity13.
After acute gastroenteritis, around 10% of individuals may develop post-infectious irritable bowel syndrome (IBS). Even after the infection resolves, damage to the gut lining and microbiome can allow inflammatory signals to persist, resulting in long-term symptoms that may last months or years14. Supporting microbiome recovery is therefore an important part of recovery.
Research across both children and adults has explored how specific probiotic strains may help shorten symptom duration and support gut recovery during gastroenteritis.
Probiotics may be useful tools for supporting gut microbiome recovery after gastroenteritis. While evidence for preventing infection is limited, research consistently shows reductions in symptom duration and severity. Probiotics are generally considered safe and well tolerated, including in higher-risk groups such as infants and older adults.
They should be used alongside standard care. Patients should be encouraged to prioritise hydration, gradually reintroduce fluids and foods, and begin with simple, easily digestible meals. Starting evidence-based probiotics early may support microbiome recovery and potentially reduce the risk of post-infectious IBS.
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