Food Poisoning in Adults - Symptoms

What are the usual symptoms of food poisoning?

  • The main symptom is diarrhoea, often with being sick (vomiting) as well. Diarrhoea is defined as "loose or watery stools (faeces), usually at least three times in 24 hours". Blood or mucus can appear in the stools with some infections.
  • Crampy pains in your tummy (abdomen) are common. Pains may ease for a while each time you pass some diarrhoea.
  • You may feel hot one minute and cold and shivery the next, and achy all over. These are symptoms of a high temperature (fever) which sometimes develops along with the tummy symptoms.

If vomiting occurs, it often lasts only a day or so but sometimes longer. Diarrhoea often continues after the vomiting stops and commonly lasts for several days or more. Slightly loose stools may persist for a week or so further before a normal pattern returns. Sometimes the symptoms last longer.

The vomiting and diarrhoea usually start hours or a very few days after eating the infected food. Afterwards, you often feel drained and washed out for a few days, while you regain your appetite and "oomph".

Symptoms of lack of fluid in the body

Diarrhoea and vomiting may cause lack of fluid in the body (dehydration). Consult a doctor quickly if you suspect you are becoming dehydrated. Mild dehydration is common and is usually easily reversed by drinking lots of fluids. Severe dehydration can be fatal unless quickly treated because the organs of your body need a certain amount of fluid to function.

Symptoms of dehydration in adults include:

  • Tiredness.
  • Dizziness or light-headedness.
  • Headache.
  • Muscle cramps.
  • Sunken eyes.
  • Passing less urine.
  • A dry mouth and tongue.
  • Weakness.
  • Becoming irritable.

Symptoms of severe dehydration in adults include:

  • Profound loss of energy or enthusiasm (apathy).
  • Weakness.
  • Confusion.
  • A fast heart rate.
  • Producing very little urine.
  • Coma - may occur.

Severe dehydration is a medical emergency and immediate medical attention is needed.

Dehydration in adults is more likely to occur in:

  • Elderly or frail people.
  • Pregnant women.
  • People with severe diarrhoea and vomiting. In particular, if you are not able to replace the fluid lost with enough drinks.

When do I need to seek medical advice?

You should seek medical advice if:

  • You think that you are becoming dehydrated.
  • You are vomiting a lot and can't keep fluids down at all.
  • You have blood in your stools (poo) or you vomit up blood.
  • You have severe tummy pain.
  • You have severe symptoms, or if you feel that your condition is becoming worse.
  • You have a high temperature (fever), which doesn't settle with medicines such as paracetamol, or which hangs about for three days or more.
  • Your symptoms are not settling; for example, vomiting for more than 1-2 days, or diarrhoea that does not start to settle after 3-4 days.
  • Your infection was caught abroad.
  • You are elderly or have an underlying health problem such as diabetes, epilepsy, inflammatory bowel disease, kidney disease.
  • You have a weakened immune system because of, for example, chemotherapy treatment, long-term steroid treatment, HIV infection.
  • You are pregnant.
  • You suspect that you may have contracted food poisoning from eating restaurant or takeaway food.
  • There are any other symptoms that you are concerned about.

Did you find this information useful?

Thanks for your feedback!

Why not subcribe to the newsletter?

We would love to hear your feedback!



Author:
Dr Mary Harding
Peer Reviewer:
Dr Laurence Knott
Document ID:
12498 (v6)
Last Checked:
02 June 2016
Next Review:
02 June 2019

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.