Food Poisoning
التسمم الغذائي
Illness caused by eating food contaminated with bacteria, viruses, parasites, or their toxins, typically causing nausea, vomiting, diarrhea, and abdominal cramps that begin within hours to a few days of eating the contaminated food. Most cases resolve on their own with rest and fluids, but symptoms that are severe, bloody, or prolonged warrant medical evaluation.
This information is for general awareness only and does not replace professional medical advice. Consult a doctor for diagnosis and treatment.
Quick answer
Food poisoning is illness caused by eating or drinking food or water contaminated with bacteria, viruses, parasites or toxins.
Symptoms usually start hours to a few days after eating: nausea, vomiting, diarrhoea, stomach cramps and sometimes fever. Most people recover at home within a few days.
The main treatment is rehydration. Seek medical care for signs of dehydration, blood in the stool, high fever, symptoms lasting more than a few days, or if the person is pregnant, very young, elderly or has a weak immune system.
Symptoms
Nausea and vomiting
Diarrhoea
May be watery, and occasionally bloody.
Stomach cramps
Fever and chills
Weakness and headache
Loss of appetite
Dehydration
Thirst, dry mouth, little or dark urine, dizziness.
Symptom guides
Causes and risk factors
Causes
- Bacteria — Such as Salmonella, Campylobacter, E. coli and Listeria, commonly from undercooked meat or poultry, eggs, unpasteurised dairy, or contaminated produce.
- Viruses — Such as norovirus, spread by infected food handlers or contaminated food.
- Toxins and parasites — Some bacteria produce toxins in food left at room temperature; parasites can contaminate water or produce.
Risk factors
- Eating undercooked meat, poultry, seafood or eggs
- Poor food storage or leaving food out at warm temperatures
- Unwashed produce or contaminated water
- Poor hand hygiene when preparing food
- Pregnancy, infants, older adults, and weak immunity — These groups get sicker and face greater risk.
- Travel to places with limited food safety
How is it diagnosed?
Most cases are diagnosed from symptoms and the history of what was eaten.
Clinical assessment
Symptoms, timing, foods eaten, others affected, and signs of dehydration.
Stool tests
For severe illness, bloody diarrhoea, long duration, or when investigating an outbreak.
Blood tests
In severe illness to check hydration, kidney function or infection.
Treatment
Most food poisoning gets better without specific treatment. The priority is replacing fluids; further treatment depends on the cause and on the person and is decided by a doctor.
Rehydration
Small, frequent sips of water or oral rehydration solution.
Rest and gentle eating
Reintroduce food gradually as nausea eases.
Medical treatment when needed
Severe cases, dehydration, or infections such as Listeria need medical care; antibiotics are only for specific situations.
Hygiene
Careful handwashing and keeping away from food preparation while ill.
Avoid anti-diarrhoea medicines if you have bloody diarrhoea or high fever unless a doctor advises them.
When should you see a doctor?
Arrange a medical assessment if
- Symptoms lasting more than two or three days
- Diarrhoea with blood
- Signs of dehydration
- Pregnancy, a young child, an older adult, or a weak immune system
- Several people ill after the same meal
Seek urgent care if
- Very little or no urine, dizziness or fainting
- High fever with severe abdominal pain
- Blurred vision, difficulty speaking or swallowing, or weakness (possible botulism — an emergency)
- Persistent vomiting so you can't keep fluids down
Prevention
Wash hands, surfaces and utensils
Cook meat, poultry and eggs thoroughly
Keep raw and cooked food separate
Refrigerate leftovers promptly
Don't leave cooked food out for long.
Use safe water and wash produce
And avoid unpasteurised milk products.
Frequently asked questions
What is food poisoning?
An illness caused by eating or drinking contaminated food or water.
How soon do symptoms start?
It varies with the cause — from a few hours to a few days after eating.
How long does food poisoning last?
Most cases settle within one to a few days, though some infections last longer.
Is food poisoning contagious?
Some causes (such as norovirus) can spread from person to person, so handwashing matters.
What should I eat and drink?
Sip fluids frequently, and reintroduce plain foods as you feel able.
When is food poisoning serious?
With dehydration, bloody diarrhoea, high fever, neurological symptoms, or in pregnant, elderly, very young or immunocompromised people.
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Medical sources
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