Food poisoning is characterised by the sudden onset of vomiting and/or diarrhoea sometimes accompanied by abdominal pain, a high temperature and headache. It occurs as a result of infection caused by contaminated food. The infection can be passed on from one person to another.


Food contamination can be caused by bacteria, bacterial toxins (chemicals produced by bacteria), viruses, insecticides, chemicals and poisonous fungi or berries.

Increasing concern about food safety in Britain has focused on the type of food poisoning caused by bacteria and their toxins. The bacteria causing most concern are Campylobacter, E. Coli, Salmonella, Clostridium, Staphylococcus, Bacillus and Listeria. In the right conditions, bacteria can multiply very quickly indeed. They need water and a temperature of between 5 and 60ºC. Bacteria can commonly be found in raw and cooked meat and poultry, meat products, processed meat, fish, shellfish, eggs and egg products, dairy produce especially soft cheeses and unpasteurised milk, contaminated water, rice and cereals.

Avoiding Food Poisoning

  • Check 'use by' and 'best before' dates on food Avoid foods with damaged packaging Wash your hands thoroughly before eating or preparing food and after going to the toilet or stroking pets Wash hands, work surfaces, chopping boards and utensils thoroughly between handling raw and cooked food. Prepare and store raw and cooked food separately and pack them in separate shopping bags Always store food at the correct temperature. A fridge thermometer should always show a temperature of below 5ºC. Take refrigerated and frozen food straight home after shopping and put it straight into the fridge or freezer. Do not leave food in a car or on a kitchen work surface for long periods of time Keep all pets away from food, utensils, crockery and food preparation areas Always cook food properly, especially if you are using a microwave. Follow instructions or recipes carefully Cover any cuts and grazes when you are preparing food Clean dishcloths regularly with disinfectant or bleach or use disposable varieties Report any examples of poor food hygiene in shops or restaurants to the local council's environmental health department When abroad, drink bottled or boiled water. Avoid ice-lollies, drinks containing ice-cubes, buffets, unpasturised dairy produce, ice creams and frozen desserts. Avoid salads and raw vegetables unless they have been peeled or thoroughly washed in bottled or boiled water. Fresh, well-cooked, piping hot food is the safer option along with fruit that can be peeled or shelled
  • Avoid raw or lightly cooked eggs e.g. mousses, hollandaise sauce, mayonnaise and meringues.


During a bout of diarrhoea water and salts are lost from the body. To replace them, drink plenty of fluid until the diarrhoea subsides. Fluid can consist of uncontaminated water (bottled or boiled and cooled if you are abroad) or an oral rehydration solution (ORS) which can be bought from a pharmacy. In an emergency you can make your own oral rehydration solution by dissolving one teaspoon of salt and eight teaspoons of sugar in one litre of boiling water or fruit juice. Leave the solution to cool then drink half a litre of solution every hour or quarter of a litre every half an hour until the diarrhoea clears up. Keep the solution in a refrigerator and remake it every day. Home-made solutions should only be used in an emergency because the salt and sugar content may be inaccurate. The concentration of salt and sugar to water is vitally important especially in babies, young children and the elderly.

Food poisoning caused by some bacteria can be treated with antibiotics.

When To See A Doctor

All cases of suspected food poisoning should be reported to a doctor.

Additional Information

Information about diarrhoea is also available from this pharmacy.

For additional information about food poisoning, contact the Digestive Disorders Foundation, 3 St Andrews Place, London, NW1 4LB. Tel: 0171 486 0341. Fax: 0171 224 2012. Website address: