Food poisoning and viral gastroenteritis are among the most common acute illnesses presenting at the pharmacy counter, particularly during warmer months when bacterial contamination of food is more likely. According to the Food Standards Agency, there are approximately 2.4 million cases of foodborne illness in the UK each year. Most are self-limiting, but community pharmacists play an important role in advising on self-care, recommending appropriate OTC products and identifying patients who need urgent medical attention.
Recognising food poisoning vs viral gastroenteritis
While the management is largely the same for both, the history can help distinguish them:
| Feature | Food poisoning | Viral gastroenteritis |
|---|---|---|
| Onset | 1–72 hours after eating contaminated food | 12–48 hours after contact with infected person |
| Key organisms | Campylobacter, Salmonella, E. coli, Staphylococcus aureus toxin | Norovirus, rotavirus |
| Vomiting | Variable — prominent with S. aureus toxin | Usually prominent, often the first symptom |
| Diarrhoea | Often dominant symptom | Present but may be secondary to vomiting |
| Duration | 1–7 days (varies by organism) | 1–3 days typically |
| Affected contacts | Others who ate the same food | Household members over 12–48 hours |
Self-care advice
Fluid replacement: the priority
Dehydration is the main risk, particularly in children, older adults and those with chronic conditions. According to NICE CKS, fluid replacement is the cornerstone of management:
For adults: Encourage frequent sips of water, clear broth or dilute squash. Oral rehydration salts (ORS) are beneficial but not essential in most adults who can drink freely. Avoid coffee and alcohol, which can worsen dehydration.
For children: ORS sachets are first-line according to NICE guidelines. Reconstitute with the correct volume of clean water. Offer frequent small sips rather than large volumes, which may provoke further vomiting. Continue breastfeeding in infants alongside ORS.
Signs of dehydration to watch for: reduced urine output or dark-coloured urine, dry mouth and lips, dizziness on standing, sunken eyes (in children), and lethargy.
Dietary advice
The traditional "BRAT diet" (bananas, rice, applesauce, toast) is no longer specifically recommended by UK guidance, but the principle holds: bland, easily digestible foods as tolerated, introduced gradually. There is no need to "starve" the illness — eating when hungry is appropriate and may speed recovery.
Dairy products may worsen symptoms in some people due to temporary lactose malabsorption, particularly after viral gastroenteritis. This usually resolves within 1–2 weeks.
OTC medicines
Loperamide (adults and children over 12): 4mg initially, then 2mg after each loose stool, maximum 16mg daily for up to 48 hours. According to BNF guidance, loperamide is suitable for symptomatic relief of acute diarrhoea in adults. It should not be used if the patient has bloody diarrhoea, high fever, or suspected inflammatory bowel disease.
Anti-emetics: Domperidone and other prescription anti-emetics are not available OTC. For adults, ginger preparations and oral rehydration remain the mainstay. For children, no OTC anti-emetics are recommended — fluid replacement is the priority.
Paracetamol: Appropriate for managing fever and abdominal cramping discomfort. Avoid NSAIDs (ibuprofen) during acute gastroenteritis as they can irritate the gastric mucosa and, rarely, worsen renal function in dehydrated patients.
Buscopan (hyoscine butylbromide): May help with abdominal cramping. Available P medicine for adults and children over 12.
When to refer urgently
Pharmacists should direct patients to urgent medical care (GP same-day, 111 or A&E depending on severity) if any of the following apply:
- Blood or mucus in stools — suggests invasive bacterial infection or inflammatory bowel disease
- Fever above 38.5°C lasting more than 24 hours
- Unable to keep fluids down for more than 24 hours (adults) or 6–8 hours (children)
- Significant dehydration signs — confusion, not passing urine, rapid pulse
- Recent travel to tropical/subtropical regions — parasitic or unusual bacterial causes may need specific treatment
- Immunocompromised patients — including those on immunosuppressants, chemotherapy or with HIV
- Babies under 6 months — lower threshold for dehydration
- Symptoms lasting more than 7 days without improvement
- Suspected botulism — descending paralysis, difficulty swallowing, blurred vision after eating preserved or vacuum-packed foods (call 999)
Prevention advice
Pharmacists can reinforce food safety messages, particularly during summer:
- Cook food thoroughly — use a food thermometer where possible; poultry should reach 75°C internally.
- Refrigerate promptly — do not leave cooked food at room temperature for more than 2 hours (1 hour above 30°C).
- Separate raw and cooked foods — use different chopping boards and utensils.
- Hand washing — before food preparation and after using the toilet. Alcohol gel is less effective against norovirus than soap and water.
- Stay off work/school for at least 48 hours after the last episode of vomiting or diarrhoea (PHE guidance).
Finding pharmacy advice
Community pharmacists can advise on gastroenteritis management and supply appropriate OTC treatments without a GP appointment. Use PharmSee's pharmacy finder to locate a pharmacy near you, or explore pharmacy careers in community health.
Sources: NHS Food Poisoning, NICE CKS Gastroenteritis, BNF Acute Diarrhoea treatment summary.