What Is Food Poisoning? Symptoms, Causes, Treatment and Prevention

Created: 27.11.2024 · Last Updated: 10.08.2026 · Category: Infectious Diseases · Prepared by the Academic Hospital Web and Editorial Board.

Food poisoning, or foodborne illness, is a broad term describing illnesses caused by eating or drinking food contaminated with harmful microorganisms, microbial toxins or certain chemicals.

Bacteria, viruses, parasites and toxins can cause different forms of foodborne disease. Depending on the cause, symptoms may begin within a few hours, several days or, in some infections, even longer after exposure.

Dehydration is an important concern: Repeated vomiting and diarrhoea can cause significant fluid and electrolyte loss, particularly in young children, older adults and people with certain underlying health conditions.

What Is Food Poisoning?

Foodborne illness can occur through different mechanisms:

  • Infection: Bacteria, viruses or parasites in contaminated food cause infection after entering the body.
  • Intoxication: Toxins already present in food, or certain chemicals, cause illness.

This distinction is important because the onset, duration and treatment can vary considerably between different causes.

What Causes Food Poisoning?

Common foodborne pathogens and toxins include:

  • Salmonella
  • Campylobacter
  • Certain strains of Escherichia coli (E. coli)
  • Listeria monocytogenes
  • Clostridium perfringens
  • Staphylococcus aureus toxins
  • Norovirus
  • Hepatitis A virus
  • Certain parasites
  • Botulinum toxin and other foodborne toxins

Risk increases when foods are undercooked, stored incorrectly, prepared with poor hand hygiene, exposed to contaminated water or cross-contaminated by raw meat, poultry or seafood.

Which Foods Carry a Higher Risk?

  • Raw or undercooked poultry
  • Raw or undercooked meat
  • Raw or undercooked eggs
  • Raw or undercooked seafood and shellfish
  • Unpasteurised milk, dairy products and juices
  • Unwashed fruit and vegetables
  • Raw sprouts
  • Perishable prepared foods stored at unsafe temperatures

Food does not need to look, smell or taste spoiled to contain disease-causing microorganisms.

What Are the Symptoms of Food Poisoning?

Common symptoms include:

  • Diarrhoea
  • Abdominal pain or cramps
  • Nausea
  • Vomiting
  • Fever
  • Fatigue or feeling generally unwell

Some infections can cause bloody diarrhoea, high fever or systemic illness. Rare toxin-mediated illnesses may predominantly affect the nervous system.

How Quickly Do Food Poisoning Symptoms Begin?

The incubation period varies greatly according to the cause.

Some toxin-mediated illnesses can begin within hours of eating contaminated food, while bacterial, viral and parasitic infections may take several days or longer to cause symptoms.

The last meal you ate is not necessarily the cause. When investigating possible foodborne illness, clinicians may ask about foods eaten over a wider period depending on the suspected organism's incubation period.

How Is Food Poisoning Diagnosed?

Many mild and short-lived foodborne illnesses do not require laboratory identification of the specific organism.

Assessment may include symptoms, their timing, recent foods, travel, whether other people who ate the same food became ill, and individual risk factors.

When clinically indicated, investigations may include:

  • Stool culture or molecular stool testing
  • Complete blood count
  • Kidney function tests
  • Electrolyte levels
  • Blood cultures or additional investigations when systemic infection is suspected

Testing may be particularly important with bloody diarrhoea, severe or prolonged illness, high fever, immunosuppression or a suspected outbreak.

How Is Food Poisoning Treated?

Many cases improve with supportive treatment. The main priority is preventing and treating dehydration and electrolyte loss.

Fluids

If fluids can be kept down, take small and frequent amounts of water and other appropriate fluids. Oral rehydration solution can help replace water and electrolytes when fluid loss is significant.

Severe dehydration or persistent vomiting may require intravenous fluids in hospital.

Eating During Recovery

Complete fasting is generally unnecessary. Once nausea improves, food can be resumed according to tolerance.

Fatty, spicy or other foods that clearly worsen symptoms can temporarily be avoided. A restrictive “banana-rice-potato” type diet is not required for every patient.

Anti-Diarrhoeal Medication

Some adults may use anti-diarrhoeal medication for symptom relief in selected situations. However, these medicines should not be used without medical advice when there is bloody diarrhoea or high fever.

Anti-motility medicines should be avoided when Shiga toxin-producing E. coli infection is suspected because they may increase the risk of haemolytic uraemic syndrome.

Are Antibiotics Needed for Food Poisoning?

Antibiotics are not required for every case of food poisoning. They do not treat viral infections, and many uncomplicated bacterial foodborne illnesses also resolve without antibiotics.

The decision depends on:

  • The suspected or confirmed organism
  • Severity of illness
  • Age and immune status
  • Risk of infection spreading beyond the intestine

Do not self-start antibiotics. Antibiotics may increase the risk of serious complications such as haemolytic uraemic syndrome in some Shiga toxin-producing E. coli infections.

Who Is at Higher Risk of Severe Foodborne Illness?

  • Children younger than 5
  • Adults aged 65 and over
  • Pregnant people and unborn babies
  • People with weakened immune systems
  • People receiving cancer treatment
  • Organ transplant recipients
  • People with certain chronic medical conditions

Some foodborne infections, particularly Listeria, can have important consequences during pregnancy even when the pregnant person has relatively mild symptoms.

When Should You See a Doctor?

Seek medical assessment if you develop:

  • Bloody diarrhoea
  • Diarrhoea lasting more than 3 days
  • A high fever around 38.9°C / 102°F or above
  • Vomiting so frequently that fluids cannot be kept down
  • Marked reduction in urination
  • Dry mouth or throat
  • Significant dizziness on standing
  • Severe or worsening abdominal pain
  • A significant deterioration in general condition

Pregnant people, young children, older adults and people with weakened immunity may require earlier assessment.

Double vision, drooping eyelids, difficulty speaking or swallowing, marked muscle weakness or difficulty breathing require emergency assessment. These symptoms may occur with botulism, a rare but serious foodborne illness. In Türkiye, call 112 Emergency.

Bloody diarrhoea, high fever, dehydration or persistent vomiting should not be ignored.

Book an Appointment

How Can Food Poisoning Be Prevented?

1. Keep Clean

Wash hands before and after preparing food, clean food-contact surfaces and wash fruit and vegetables appropriately.

2. Separate Raw and Cooked Foods

Prevent raw meat, poultry and seafood from contaminating ready-to-eat foods. Separate equipment and cutting boards can help prevent cross-contamination.

3. Cook Thoroughly

Cook meat, poultry, eggs and seafood adequately. A food thermometer can be useful for confirming safe internal temperatures rather than relying on appearance alone.

4. Keep Food at Safe Temperatures

Do not leave perishable foods at room temperature for unnecessarily long periods and refrigerate foods that require a cold chain appropriately.

5. Use Safe Water and Raw Materials

Choose safe drinking water, pasteurised products and foods prepared and stored under appropriate conditions.

Have Persistent Food Poisoning Symptoms Assessed

Persistent diarrhoea, fever, vomiting, dehydration or suspected foodborne infection can be evaluated with appropriate examination and laboratory testing.

Frequently Asked Questions

How quickly does food poisoning begin?
The onset depends on the cause. Some toxin-mediated illnesses begin within hours, while bacterial, viral or parasitic illnesses may take several days or longer to produce symptoms.
How long does food poisoning last?
Duration depends on the cause. Many mild foodborne illnesses improve within a few days, although some infections can last for a week or longer.
What should you drink with food poisoning?
The main goal is to prevent dehydration. Water and other tolerated appropriate fluids can be taken in small, frequent amounts. Oral rehydration solutions can be used when significant fluid and electrolyte loss occurs.
Are antibiotics used for food poisoning?
Antibiotics are not required for every case. They do not work against viral illnesses and are not routinely recommended for some bacterial infections. The decision depends on the organism, severity of illness and individual risk factors.
Can anti-diarrhoeal medicine be used for food poisoning?
It may be appropriate for some adults in selected circumstances, but it should not be used without medical advice when there is bloody diarrhoea or high fever. Anti-motility medicines should be avoided with Shiga toxin-producing E. coli infection.
Are probiotics necessary for food poisoning?
The potential benefit of probiotics varies according to the product, organism and individual patient. Preventing dehydration remains the main treatment priority; probiotics are not mandatory or standard treatment for every case.
When should you go to hospital with food poisoning?
Medical assessment is needed for bloody diarrhoea, diarrhoea lasting more than 3 days, high fever, vomiting that prevents fluid intake, significant dehydration, severe abdominal pain or worsening general condition. Pregnant people, young children, older adults and immunocompromised people may require earlier assessment.
Academic Hospital note: Preventing dehydration is one of the most important aspects of food poisoning treatment. Antibiotics, anti-diarrhoeal medicines and other treatments are not appropriate for every patient. You can book an appointment for persistent symptoms; severe or rapidly worsening symptoms require urgent medical assessment.

References

  1. Academic Hospital. Gıda Zehirlenmesi Nedir? Belirtileri Nelerdir? Nasıl Tedavi Edilir?
  2. Centers for Disease Control and Prevention. Food Poisoning Symptoms
  3. Centers for Disease Control and Prevention. Preventing Food Poisoning
  4. Centers for Disease Control and Prevention. Clinician Brief: Food Safety
  5. Centers for Disease Control and Prevention. Treatment of E. coli Infection
  6. World Health Organization. Five Keys to Safer Food
  7. NHS. Food Poisoning
  8. U.S. Food and Drug Administration. People at Risk of Foodborne Illness