What Is Foodborne Illness? Symptoms, Treatment and Prevention

Editorially reviewed by: A to Zen Therapies Editorial Team in accordance with our Editorial Policy.

Foodborne illness—commonly called food poisoning—can develop after eating food or drinking water contaminated by harmful microorganisms, toxins or chemicals.

Common symptoms include diarrhoea, vomiting, nausea, abdominal pain, fever and feeling generally unwell. Many cases improve without specific treatment, but dehydration and certain infections can become serious, particularly for young children, older adults, pregnant people and anyone with a weakened immune system.

The food responsible is not necessarily the last meal eaten. Symptoms may begin within hours, several days or occasionally weeks after exposure.

Safe preparation, storage and hand hygiene can reduce the risk of foodborne illness, although contamination can occur at several stages of the food chain.

Quick Answer

Foodborne illness is an infection or harmful reaction caused by consuming contaminated food or drink. Symptoms often include nausea, vomiting, diarrhoea, abdominal cramps, fever and fatigue.

Most uncomplicated cases improve with rest, small frequent drinks and food as tolerated. Seek urgent medical advice for bloody diarrhoea, inability to retain fluids, signs of dehydration, persistent symptoms or illness affecting someone at higher risk of complications.

⭐ What Is Foodborne Illness?

Foodborne illness is a broad term covering diseases caused by contaminated food or drink.

Possible causes include:

• Bacteria such as Salmonella, Campylobacter, pathogenic E. coli and Listeria

• Viruses such as norovirus

• Parasites such as Giardia

• Toxins produced by microorganisms

• Naturally occurring toxins

• Harmful chemicals or contaminants

Food poisoning is not always caused by food that looks, smells or tastes spoiled. Pathogens can be present without causing an obvious change.

Key Takeaways

• Food poisoning can be caused by bacteria, viruses, parasites or toxins.

• Symptoms may begin hours, days or occasionally weeks after exposure.

• The last meal eaten is not necessarily the cause.

• Preventing dehydration is the main priority in many uncomplicated cases.

• Oral rehydration solutions may help replace lost fluid and salts.

• The BRAT diet is unnecessarily restrictive as a long-term recovery diet.

• Ginger, herbs and essential oils do not eliminate a foodborne infection.

• Bloody diarrhoea, persistent vomiting and neurological symptoms require assessment.

• Young children, older adults, pregnant people and immunocompromised people face greater risks.

• People with vomiting or diarrhoea should avoid preparing food for others.

• Suspected outbreaks or unsafe businesses can be reported to the local food-safety team.

• Antibiotics are only appropriate for selected infections.

Table of Contents

1. What Causes Foodborne Illness?

2. When Do Symptoms Begin?

3. Common Food-Poisoning Symptoms

4. When to Seek Medical Help

5. Who Is More Vulnerable?

6. What to Do at Home

7. Medicines and “Natural Remedies”

8. Preventing the Spread to Other People

9. Reporting Suspected Food Poisoning

10. Preventing Foodborne Illness

11. Frequently Asked Questions

What Causes Foodborne Illness?

Contamination can happen during farming, manufacturing, transport, retail, preparation or storage.

Common routes include:

• Undercooked meat, poultry, eggs or seafood

• Unpasteurised milk or dairy products

• Unwashed fruit and vegetables

• Raw sprouts

• Contaminated water

• Poor hand hygiene

• Cross-contamination between raw and ready-to-eat food

• Inadequate refrigeration

• Food left at room temperature for too long

• An infected person preparing food

• Contaminated equipment or work surfaces

Norovirus can spread through food, contaminated surfaces and close contact with an infected person. This means several household members becoming ill does not necessarily prove that one particular meal was responsible.

When Do Symptoms Begin?

The incubation period depends on the microorganism or toxin involved.

Some toxin-related illnesses can begin within a few hours. Other infections may take several days, and a few can take considerably longer. The NHS guide to food poisoning explains that symptoms usually begin within a few hours or days, but may occasionally take weeks to appear.

When considering a possible source, think about:

• Meals eaten over the preceding days

• Restaurants, takeaways or catered events

• Other people who ate the same food

• Recent travel

• Untreated water

• Contact with farm animals or reptiles

• Food recalls

• Ill household members

Do not automatically blame the most recent meal.

Common Food-Poisoning Symptoms

Possible symptoms include:

• Feeling sick

• Vomiting

• Watery diarrhoea

• Abdominal cramps

• Fever

• Chills

• Headache

• Muscle aches

• Reduced appetite

• Fatigue

• Feeling generally unwell

Some infections may cause bloody diarrhoea or mucus. Others can occasionally produce neurological symptoms, including blurred vision, difficulty swallowing, muscle weakness or confusion.

Symptoms alone cannot reliably identify the organism. A clinician may request a stool sample or other tests when symptoms are severe, prolonged, unusual or associated with an outbreak.

📊 Evidence Snapshot: Foodborne illness is not one condition with one incubation period or treatment. The clinically important distinctions include:

• Whether the illness is caused by infection, toxin or chemical contamination

• Whether the person can maintain hydration

• Whether blood is present in the stool

• Whether neurological symptoms have developed

• How long vomiting or diarrhoea has continued

• Whether the person belongs to a higher-risk group

• Whether several people became ill after the same exposure

This is why home remedies should not replace assessment when warning signs are present.

Food Poisoning or Another Condition?

Vomiting and diarrhoea can also result from:

• Person-to-person gastroenteritis

• Medicine side effects

• Migraine

• Appendicitis

• Inflammatory bowel disease

• Irritable bowel syndrome

• Food intolerance

• Pregnancy-related nausea

• Other abdominal or metabolic conditions

Pregnancy nausea does not usually cause fever or diarrhoea. Readers can compare typical pregnancy symptoms in our guide to morning sickness.

A food allergy is different from food poisoning. Swelling of the lips or tongue, wheezing, difficulty breathing, throat tightness or collapse may indicate a severe allergic reaction and require emergency assistance.

When to Seek Medical Help

The NHS guidance on diarrhoea and vomiting recommends urgent advice when someone:

• Cannot keep fluids down

• Has bloody diarrhoea or rectal bleeding

• Continues to show dehydration despite oral rehydration

• Has vomiting lasting more than two days

• Has diarrhoea lasting more than seven days

• Is a baby under 12 months and the caregiver is worried

• Is a young child who stops breast or bottle feeding

• Is a child under five with fewer wet nappies or other dehydration signs

Other reasons to seek prompt assessment include:

• Severe or worsening abdominal pain

• High or persistent fever

• Recent foreign travel

• Diarrhoea after recent antibiotic use

• Substantial weakness or drowsiness

• Symptoms during pregnancy

• Illness in someone with significant medical conditions or immune suppression

Seek emergency assistance for:

• Vomit containing blood or resembling coffee grounds

• Green vomit

• Sudden, severe abdominal pain

• Severe breathing difficulty

• Collapse, seizure or loss of consciousness

• Marked confusion

• New difficulty swallowing, speaking or moving

• Blue, grey, very pale or blotchy skin

💡 Expert Tip: Do not use thirst as the only measure of dehydration. Watch for dark urine, urinating less frequently, dizziness when standing, dry mouth, unusual drowsiness, sunken eyes or fewer wet nappies. Young children and older adults may deteriorate more quickly.

Who Is More Vulnerable?

Food poisoning can affect anyone, but FoodSafety.gov’s vulnerable-groups guidance identifies four groups at increased risk of serious illness:

• Adults aged 65 and over

• Children younger than five

• Pregnant people

• People with weakened immune systems

Immune suppression may be related to a health condition or treatment such as chemotherapy, transplant medicines or certain immune-modifying drugs.

Foodborne illness during pregnancy

Pregnancy can increase vulnerability to particular infections. Listeriosis may cause relatively mild flu-like or gastrointestinal symptoms in the pregnant person while creating serious pregnancy risks.

Contact a GP, midwife or maternity service if you are pregnant and:

• Develop fever or gastrointestinal symptoms after a suspected exposure

• Have eaten a recalled high-risk product

• Are concerned about possible listeria exposure

• Cannot retain fluids

• Notice reduced fetal movement at a stage when movement is normally established

What to Do at Home

Many uncomplicated cases can be managed at home while monitoring for warning signs.

Prioritise fluids

Take small, frequent sips if drinking a full glass triggers nausea.

Suitable fluids may include:

• Water

• Diluted squash

• Oral rehydration solution

• Clear soup or broth

A pharmacist can advise about oral rehydration sachets. These contain carefully balanced amounts of glucose and salts and may be particularly useful after repeated vomiting or diarrhoea.

Very sugary or fizzy drinks can sometimes worsen diarrhoea.

Continue breast or bottle feeding a baby. If the baby is vomiting, smaller and more frequent feeds may be easier to tolerate.

Eat when you feel able

There is no need to follow a prolonged BRAT diet consisting only of bananas, rice, apple sauce and toast. Although bland foods may feel comfortable initially, such a limited diet does not provide balanced nutrition.

Begin with small portions of foods you can tolerate, such as:

• Toast

• Rice

• Potatoes

• Soup

• Pasta

• Banana

• Cooked vegetables

• Yoghurt, if tolerated

• Eggs or another protein source, once appetite returns

Fatty, spicy or very rich meals may be uncomfortable during the early stage.

Rest and monitor symptoms

Keep track of:

• How often vomiting or diarrhoea occurs

• Fluid intake

• Urination

• Fever

• Blood or mucus in the stool

• New pain

• Other people who became ill

This information may help a clinician or public-health investigator.

Replacing lost fluids is usually the immediate priority; food can be reintroduced gradually according to appetite and tolerance.

Medicines and “Natural Remedies”

Anti-diarrhoeal medicines

Anti-diarrhoeal medicines are not appropriate for everyone. They may be unsuitable for children, people with bloody diarrhoea or those with certain infections.

Ask a pharmacist or clinician before using them, particularly when fever, severe abdominal pain, blood or mucus is present.

Antibiotics

Most foodborne illnesses do not require antibiotics. Antibiotics only treat susceptible bacteria—not viruses or preformed toxins—and may be unnecessary or harmful in certain infections.

Take antibiotics only when prescribed following appropriate assessment.

Ginger

Ginger tea may feel soothing for mild nausea, but it does not kill foodborne pathogens, neutralise toxins or prevent complications. Stop using it if it worsens symptoms, and check for interactions if you take medicines.

Essential oils

An essential oil diffuser may be used by some people for fragrance or relaxation, but it does not treat food poisoning. Strong smells may worsen nausea, and essential oils should not be swallowed as an infection remedy.

Preventing the Spread to Other People

Some causes of suspected food poisoning are highly contagious.

To reduce transmission:

• Wash hands thoroughly with soap and water after using the toilet and before touching food.

• Clean toilets, taps, handles and commonly touched surfaces.

• Do not share towels.

• Wash soiled clothing and bedding separately at an appropriate temperature.

• Avoid preparing food for other people.

• Do not visit hospitals or care homes while symptomatic.

• Follow workplace or school infection-control requirements.

People with vomiting or diarrhoea should normally remain away from work, school or nursery until at least 48 hours after the last episode. A different exclusion period may apply for a diagnosed infection or particular occupation.

Food handlers and people working with vulnerable patients or children should tell their employer promptly and follow occupational-health or public-health advice.

Reporting Suspected Food Poisoning

If you suspect food from a restaurant, takeaway, shop or delivery caused illness, record:

• Where and when it was purchased

• What was eaten

• The date and time symptoms began

• Who else ate the food

• Whether anyone else became ill

• The product name, batch number and use-by date

• Receipts, order confirmations and packaging

• Any medical test results

Do not attempt to culture or test food at home. Do not taste it again.

Place suspect packaging where it cannot contaminate other food and ask the local food-safety team whether the product should be retained or discarded.

In England, Wales and Northern Ireland, the Food Standards Agency’s reporting service can direct consumers to the appropriate local team. Current food recalls and alerts can also be checked online.

When legal advice may be considered

Medical care and public-health reporting should come before compensation questions.

If laboratory-confirmed Salmonella causes serious harm after a suspected commercial exposure, preserving medical records, receipts and public-health correspondence may be useful. Readers dealing with a Washington State incident may encounter a Seattle salmonella lawyer when comparing local legal options.

This commercial provider is not a medical or public-health authority, and inclusion does not guarantee that a legal claim exists or that compensation will be obtained.

Preventing Foodborne Illness

The Food Standards Agency organises food-hygiene practices around the four Cs of food safety:

Cleaning

• Wash hands before preparing food and after handling raw meat, using the toilet, changing nappies or touching animals.

• Clean worktops, chopping boards and utensils.

• Do not rely on appearance alone to judge cleanliness.

• Avoid washing raw chicken because splashing can spread bacteria.

Cooking

• Cook food thoroughly.

• Follow package instructions.

• Reheat leftovers until steaming hot throughout.

• Use a clean food thermometer where appropriate.

• Do not eat food that should be cooked if the centre remains raw.

Chilling

• Refrigerate perishable food promptly.

• Keep the refrigerator at an appropriate temperature.

• Follow use-by dates.

• Defrost food safely.

• Do not leave cooked food standing at room temperature for prolonged periods.

The Food Standards Agency’s chilling guidance explains how correct refrigeration and defrosting help limit bacterial growth.

Avoiding cross-contamination

• Keep raw meat and poultry away from ready-to-eat foods.

• Store raw products in sealed containers at the bottom of the refrigerator.

• Use clean chopping boards and utensils.

• Wash equipment thoroughly between uses.

• Keep cooked food away from surfaces that held raw ingredients.

The FSA explains that cross-contamination can occur between foods, surfaces and equipment.

Foodborne Illness and A to Zen Therapies Appointments

Massage, acupuncture and other complementary treatments do not treat food poisoning, dehydration or infection.

Do not attend an A to Zen Therapies appointment while experiencing vomiting or diarrhoea. Reschedule until you have been free from these symptoms for at least 48 hours, or longer if a healthcare or public-health professional has given different advice.

Continue Exploring Nutrition and Digestive Health

Food safety is an important part of healthy eating. Explore our Nutrition Hub for evidence-informed articles about balanced diets, digestive health, nutrients and practical food choices.

Frequently Asked Questions

How quickly does food poisoning start?

It may begin within hours, days or occasionally weeks. The timing depends on the microorganism or toxin involved.

Is the last meal I ate responsible?

Not necessarily. Some infections have longer incubation periods, so food eaten several days earlier may be relevant.

How long does food poisoning last?

Many uncomplicated cases improve within a week. Vomiting usually resolves sooner than diarrhoea. Persistent or worsening symptoms require advice.

What should I drink?

Take small, frequent sips of water or an oral rehydration solution. A pharmacist can recommend an appropriate product.

Is the BRAT diet recommended?

A few bland foods may feel comfortable initially, but a prolonged diet limited to bananas, rice, apple sauce and toast is unnecessarily restrictive. Eat a wider range as tolerated.

Can ginger cure food poisoning?

No. Ginger may feel soothing for nausea, but it cannot eliminate an infection or neutralise a toxin.

Should I take antibiotics?

Only when prescribed. Many foodborne illnesses are viral or resolve without antibiotics, and certain bacterial infections require careful treatment decisions.

Can I take anti-diarrhoeal medicine?

Ask a pharmacist or clinician first. These medicines may be unsuitable for children or when blood, fever or severe pain is present.

When can I return to work?

The usual rule is at least 48 hours after the final episode of vomiting or diarrhoea. Some infections and occupations require longer exclusion.

Should I save the suspect food?

Keep packaging, receipts and product information. Ask the local food-safety team whether

the actual food should be retained; do not test or taste it yourself.

How can I report suspected food poisoning?

Contact the relevant local council food-safety or environmental-health team. The Food Standards Agency provides an online reporting route for England, Wales and Northern Ireland.

References

• NHS — Food poisoning

• NHS — Diarrhoea and vomiting

• UK Health Security Agency — Stomach bugs

• Food Standards Agency — Food safety and the four Cs

• Food Standards Agency — Report a food problem

• Food Standards Agency — Recalls and alerts

• Food Standards Agency — Preventing cross-contamination

• FoodSafety.gov — People at increased risk