How long after eating something do you get food poisoning

Food poisoning is not usually serious. Most people get better within a few days. You can normally treat yourself or your child at home.

Food poisoning is usually caused by eating food that is contaminated by bacteria.

Symptoms of food poisoning

The main symptoms of food poisoning include:

  • feeling sick (nausea)
  • vomiting
  • diarrhoea, which may contain blood or mucus
  • stomach cramps and abdominal (tummy) pain
  • a lack of energy and weakness
  • loss of appetite
  • a high temperature (fever)
  • aching muscles
  • chills

The symptoms usually start within 1 to 2 days after eating contaminated food. Symptoms can start at any point between a few hours and a few weeks later.

In most cases, these symptoms will pass in a few days and you will make a full recovery.

Causes of food poisoning

You can catch food poisoning if you eat something that has been contaminated with germs.

This can happen if food is:

  • not cooked or reheated thoroughly
  • not stored correctly – for example, it's not been frozen or chilled
  • left out for too long
  • handled by someone who's ill or has not washed their hands
  • eaten after its 'use by' date

Cross-contamination can happen if you prepare raw and cooked food on the same chopping board. Cross-contamination is where harmful bacteria are spread between food, surfaces and equipment.

Foods that can be contaminated if not handled, stored or cooked properly include:

  • raw meat and poultry
  • raw shellfish
  • unpasteurised milk
  • 'ready-to-eat' foods. These could be cooked sliced meats, pâté, soft cheeses and pre-packed sandwiches

Infections that cause food poisoning

Food poisoning is usually caused by:

  • Campylobacter bacteria - usually found on raw or undercooked meat
  • Salmonella bacteria - often found in raw or undercooked meat, raw eggs, milk, and other dairy products
  • Listeria bacteria - can be found in a pre-packed sandwiches, cooked sliced meats and soft cheeses
  • E.coli bacteria - usually caught after eating undercooked beef
  • Norovirus - spread from person to person, through contaminated food or water

Treatment for food poisoning

You can usually treat yourself or your child at home.

Stay off school or work until the symptoms have stopped for 2 days. This is when you're most infectious.

Rest and drink fluids to prevent dehydration. Try to drink plenty of water, even if you can only sip it.

Eat when you feel up to it. Try small, light meals at first and stick to bland foods, such as toast and rice until you begin to feel better.

Oral rehydration solutions (ORS) are recommended for vulnerable people, such as the elderly. These are available from pharmacies.

Non-urgent advice: Contact your GP if:

  • you're unable to keep down any fluids because you are vomiting
  • your symptoms don't start to improve after a few days
  • you have symptoms of severe dehydration such as confusion, a rapid heartbeat and passing little or no urine
  • you're pregnant
  • you're over 60
  • your baby or young child has suspected food poisoning
  • you have a long-term underlying condition. This could be inflammatory bowel disease (IBD), diabetes or kidney disease
  • you have a weak immune system – for example, because of medication, cancer treatment or HIV

Your GP may send off a sample of your poo for analysis and prescribe antibiotics. They may refer you to hospital so you can be looked after more closely.

Reporting food poisoning

If you think your food poisoning has been caused by a restaurant or other food outlet, you can report it to your local environmental health department.

Environmental health officers may investigate the food premises. They can if necessary, ensure that the business improves its standards of hygiene.

The Food Safety Authority of Ireland (FSAI) has information about reporting poor hygiene standards in a food outlet.

10 tips to preventing food poisoning

Tips to help reduce your risk of food poisoning at home:

  1. Wash your hands
  2. Wash worktops
  3. Wash dishcloths
  4. Use a separate chopping board for raw meat and fish
  5. Keep raw meat separate
  6. Store raw meat on the bottom shelf
  7. Cook food thoroughly
  8. Keep your fridge below 5 degrees Celsius
  9. Cool leftovers quickly
  10. Respect 'use-by' dates

Wash your hands

Wash and dry your hands thoroughly with soap and water (warm or cold) especially:

  • before handling food
  • after handling raw food
  • after touching the bin
  • after going to the toilet
  • after blowing your nose
  • after touching animals, including pets

Wash worktops

Wash worktops before and after preparing food. Do this particularly after they've been touched by raw meat, raw eggs, fish and vegetables. You do not need to use antibacterial sprays: hot, soapy water is fine.

Wash dishcloths

Wash dishcloths and tea towels regularly. Let them dry before you use them again. Dirty, damp cloths are the perfect place for germs to spread.

Use separate chopping boards

Use a separate chopping board to prepare raw food, such as meat and fish. This is to avoid contaminating ready-to-eat foods with harmful bacteria. This bacteria can be present in raw food before you cook it.

Keep raw meat separate

Keep raw meat away from ready-to-eat foods, such as salad, fruit and bread. This is because these foods will not be cooked before you eat them. Any bacteria that get onto the foods from the raw meat will not be killed.

Store raw meat on the bottom shelf

Always cover raw meat and store it on the bottom shelf of the fridge. This is so it cannot touch or drip onto other foods.

Cook food thoroughly

Cook poultry, pork, burgers, sausages and kebabs until steaming hot. There should be no pink meat inside. Do not wash raw meat (including chicken and turkey) before cooking. This can spread bacteria around your kitchen.

Freezing raw chicken reduces the levels of campylobacter bacteria. But it does not eliminate them completely. The safest way to kill all traces of campylobacter is by cooking chicken thoroughly.

Keep your fridge below 5 degrees Celsius

Keep your fridge temperature below 5 degrees Celsius. Use a fridge thermometer to check it. This prevents harmful germs from growing and multiplying.

Avoid overfilling your fridge. If it's too full, air can't circulate properly. This can affect the temperature.

Cool leftovers quickly

If you have cooked food that you're not going to eat straight away, cool it as soon as possible. Do this within 90 minutes. Store it in the fridge or freezer. Use any leftovers from the fridge within 2 days.

Respect 'use-by' dates

Do not eat food that's past its use-by date, even if it looks and smells okay. Use-by dates are based on scientific tests. These show how quickly harmful bugs can develop in the packaged food.


Content supplied by the NHS and adapted for Ireland by the HSE

How long after eating something do you get food poisoning
This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.

Page last reviewed: 26 April 2020
Next review due: 26 April 2023