Food Poisoning in Adults

Food poisoning is an illness caused by eating and drinking food or drink which is contaminated by germs or toxins. Gastroenteritis is a gut infection with diarrhoea, tummy ache and sometimes being sick (vomiting). Diarrhoea is defined as 'loose or watery stools (faeces), usually at least three times in 24 hours'.

What is food poisoning and what causes it?

Food poisoning means getting sick from eating food with poisonous stuff in it. But not usually the kind of poisons used by the killer in an Agatha Christie story. Usually the poison comes from some type of germ.

Many types of germs can cause food poisoning, including bacteria, viruses and parasites. Common culprits include:

You are more likely to pick up food poisoning if you are not careful about how you store and handle food, and about what and where you eat or drink.

Find out more about causes of food poisoning.

What are the symptoms?

Most often, food poisoning gives you "the runs". That is, diarrhoea - frequent, runny poos. You may also have crampy tummy ache. You may be sick (vomit) as well. You may have a high temperature (fever).

The main risk of food poisoning is losing fluid from your body and becoming too dry (dehydration). This can lead to extreme weakness or dizziness.

Read more about symptoms and when to seek medical advice.

How is it diagnosed?

Usually you don't need to be a doctor to diagnose food poisoning. It is normally pretty clear from the symptoms you have. You probably won't need any tests, unless you have been travelling abroad or your symptoms are not settling. If your diarrhoea lasts four days or more, your doctor may ask for a sample of your poo (stool) in a pot so it can be sent to the lab for testing.

Read more about the diagnosis of food poisoning.

What's the treatment?

For most of us, our clever bodies treat themselves by getting rid of the germs responsible for all that diarrhoea and being sick (vomiting). All we need to do is to drink enough fluid (water is usually best) to make up for all the liquid we are losing.

Medicines aren't usually needed for food poisoning. If you have a high temperature (fever), paracetamol  may help. Loperamide can be bought over the counter to stop diarrhoea, but it is best avoided if possible. Occasionally you may need an antibiotic to get rid of your germ.

Find out more about treatment for food poisoning.

What is the outlook for food poisoning?

Usually the symptoms only last a few hours or days, but it may take a week or more and you may feel wiped out for a few days after the diarrhoea and vomiting settle.

Complications are uncommon. The most common complication is lack of fluid in the body (dehydration). This is more likely if your health is frail, or if your immune system isn't firing on all cylinders (due to medication such as long-term steroids or chemotherapy).

Get more detail on possible complications.

How can I prevent it?

You can reduce your chances of picking up food poisoning by some common sense precautions when you store, handle or eat food. The Food Standards Agency in the UK has identified "the 4 Cs": advice on cleanliness, cooking, chilling and avoiding cross-contamination.

Using the 4 Cs advice, find out how to keep yourself safe.

Special precautions may also be needed to prevent food poisoning if you are travelling abroad. Our separate leaflet called Traveller's Diarrhoea has more details. For example, avoid water and other drinks that may not be safe, and avoid food washed in unsafe water.

Next: Symptoms

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Dr Mary Harding
Peer Reviewer:
Dr Laurence Knott
Document ID:
12498 (v6)
Last Checked:
02 June 2016
Next Review:
02 June 2019
The Information Standard - certified member

The information on this page is written and peer reviewed by qualified clinicians.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.