Overview

Food poisoning, also known as foodborne illness, is a condition caused by consuming contaminated food or beverages. It occurs when harmful bacteria, viruses, parasites, or toxins enter the body through food, leading to gastrointestinal symptoms. Each year, roughly one in six people in the United States are affected by food poisoning.

While many cases are mild and resolve within a few days, others can lead to serious complications, especially in vulnerable populations such as young children, older adults, pregnant individuals, and those with weakened immune systems.

Symptoms

Symptoms of food poisoning can begin within hours of eating contaminated food, though in some cases, they may take days to appear. The severity and duration of symptoms depend on the cause and amount of contamination.

Common symptoms include:

  • Diarrhea (sometimes watery or bloody)

  • Abdominal cramps

  • Nausea

  • Vomiting

  • Fever

  • Fatigue

In children and infants:

  • Increased irritability

  • Lethargy or lack of energy

  • Frequent diarrhea or vomiting

  • No wet diapers for hours

  • Dry mouth or tongue

Seek immediate medical care if you experience:

  • Diarrhea lasting more than three days

  • High fever (over 102°F / 39°C)

  • Blood in stool or vomit

  • Persistent vomiting preventing fluid intake

  • Signs of dehydration like dizziness, dry mouth, or low urine output

Causes

Food poisoning is primarily caused by ingesting food or beverages contaminated with harmful microorganisms or toxins. These contaminants can develop during any stage of food handling—growing, processing, storage, or preparation.

Common pathogens responsible for food poisoning include:

  • E. coli: Found in undercooked ground beef, raw vegetables, and unpasteurized milk. Symptoms typically appear 3–4 days after exposure.

  • Salmonella: Present in raw or undercooked meat, eggs, poultry, and raw produce. Symptoms develop within 6 hours to 6 days.

  • Staphylococcus aureus: A bacteria found in foods not cooked after handling, like deli meats. Symptoms can begin within 30 minutes to 8 hours.

  • Vibrio: Often associated with raw or undercooked shellfish, with symptoms starting in less than a day.

  • Norovirus: Common on unclean cooking surfaces or contaminated vegetables and shellfish. Causes symptoms in 12–48 hours.

Other causes include:

  • Parasites such as tapeworms or protozoa

  • Molds or natural toxins (e.g., mycotoxins)

  • Food allergies, which are not infections but immune responses that mimic food poisoning symptoms

Risk Factors

Certain groups are more likely to experience severe food poisoning or complications:

  • Infants and toddlers

  • Older adults (65+)

  • Pregnant individuals

  • People with weakened immune systems (e.g., HIV, cancer treatment, organ transplants)

These individuals are more susceptible to dehydration, longer illness duration, and potential hospitalization. For instance, children under five are three times more likely to be hospitalized for Salmonella poisoning than other age groups.

Diagnosis

Most cases of food poisoning are diagnosed based on symptoms and recent food intake. However, for persistent or severe symptoms, a healthcare provider may perform additional tests:

Diagnostic methods may include:

  • Medical history and symptom review

  • Stool sample to detect bacteria, viruses, or parasites

  • Blood tests to assess for infection or dehydration

  • Complete blood count (CBC) to detect immune response

  • Liver function tests, if toxin exposure is suspected

Doctors may also ask if others who ate the same food are sick or if the patient has recently traveled, especially to regions with a higher risk of foodborne illnesses.

Treatment

Treatment for food poisoning depends on the severity and the cause. Most mild cases resolve on their own within a few days.

General treatments include:

  • Hydration: Drink water, electrolyte solutions, or diluted fruit juices to replace fluids lost through diarrhea or vomiting. For children, oral rehydration solutions like Pedialyte are often recommended.

  • Rest: Allowing the body to recover through adequate rest is essential.

  • Bland diet: The BRAT diet—bananas, rice, applesauce, toast—can be soothing and easy to digest.

  • Over-the-counter medications:

    • Loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol) for diarrhea relief

    • Avoid these in infants, children, or if there is blood in the stool

If the cause is bacterial or parasitic, a provider may prescribe:

  • Antibiotics (e.g., ciprofloxacin for certain bacterial infections)

  • Antiparasitic drugs (e.g., metronidazole)

Severe dehydration may require intravenous fluids in a hospital setting.

Prevention

Many cases of food poisoning can be prevented through safe food handling practices.

Tips to prevent food poisoning include:

  • Wash hands before and after handling food

  • Sanitize cutting boards and cooking surfaces

  • Cook meats to safe temperatures: Use a food thermometer (e.g., 165°F for poultry)

  • Avoid cross-contamination: Use separate utensils for raw and cooked foods

  • Refrigerate leftovers within two hours (one hour if ambient temperature exceeds 90°F)

  • Wash produce thoroughly before eating or cooking

  • Avoid unpasteurized dairy and juices

  • Use bottled or treated water when traveling to areas with unsafe tap water

By adopting these habits, individuals can significantly lower their risk of foodborne illness.

Complications

Most food poisoning cases resolve without long-term effects. However, certain complications can arise, especially in severe or untreated cases.

Dehydration

Loss of fluids from vomiting and diarrhea can lead to dehydration.

Symptoms include:

  • Dry mouth or skin

  • Little to no urination

  • Dizziness or lightheadedness

  • Fatigue

  • Dark-colored urine

Infants and children may show:

  • Dry tongue

  • No tears while crying

  • No wet diapers for hours

  • Unusual sleepiness or fussiness

Botulism

A rare but serious complication caused by toxins from Clostridium botulinum. It can occur from improperly canned or fermented foods.

Symptoms of botulism include:

  • Blurred or double vision

  • Muscle weakness

  • Drooping eyelids

  • Slurred speech

  • Paralysis (in severe cases)

Infants can develop botulism from eating honey or soil-contaminated foods.

Botulism is a medical emergency requiring antitoxin treatment and hospital care.

Other rare complications:

  • Hemolytic uremic syndrome (from E. coli): May cause kidney failure

  • Reactive arthritis

  • Meningitis (especially in infants)

  • Nerve damage or neurological effects

  • Chronic digestive issues in severe cases

Living With Food Poisoning

Most people recover fully within a few days. Staying well-hydrated, eating a bland diet, and avoiding irritants like caffeine, alcohol, or spicy foods can support recovery. Probiotics may help restore gut balance, but should only be used after consulting a healthcare provider.

Avoid returning to work or school until at least 24 hours after symptoms subside, especially if handling food or caring for others.

Final Thoughts

Food poisoning is an unpleasant but common health issue. Fortunately, with proper care and attention to food safety, most cases can be prevented or quickly resolved. Recognizing symptoms early and staying hydrated are key to recovery. For severe or persistent symptoms, always consult a healthcare provider to rule out complications and receive proper treatment.