7 Common Signs of Food Poisoning

Food poisoning usually hits fast and hard. The most common signs are nausea, vomiting, diarrhoea, abdominal cramps, fever, headaches and lethargy (fatigue). Symptoms can start within hours of eating contaminated food and often settle in one to three days. 

Recognising these symptoms early helps you rehydrate, rest and decide when to seek medical care.

at a glance: FOOD POISONING facts

What is food poisoning and how soon do symptoms appear?

Food poisoning happens when you eat or drink something contaminated with harmful bacteria, viruses or toxins. 

Common causes include undercooked poultry, unpasteurised dairy, raw seafood and poor temperature control. Symptoms often begin within a few hours of consuming the product, though timing varies with the organism and the amount consumed.

What are the most common signs of food poisoning?

1. Nausea

That sudden, queasy feeling is often the first warning. Small sips of water or an oral rehydration solution can help you keep fluids down.

2. Vomiting

Your body is trying to expel the contaminant quickly. Frequent vomiting raises dehydration risk, so replace fluids and electrolytes often.

3. Diarrhoea

Watery, frequent bowel movements are a hallmark symptom. If diarrhoea lasts longer than three days, check in with your GP or call healthdirect.

4. Abdominal (stomach) cramps

Cramping and bloating occur as your intestines contract to move pathogens along the digestive tract. Rest, fluids and plain foods usually help.

5. Fever

A mild fever signals your immune system is fighting back. If your temperature rises above 38.5°C and doesn’t drop, seek medical advice.

6. Headaches

Fluid loss and inflammation can trigger headaches. Prioritise hydration and rest.

7. Lethargy (fatigue)

Losing fluids and nutrients can leave you feeling wiped out. Ease back into eating with light, nourishing options once you can tolerate food.

When should you see a doctor about food poisoning?

Most mild cases of food poisoning settle within 24 to 72 hours. Get medical help sooner if you have any of the following:

• Persistent vomiting or diarrhoea beyond three days
• Blood in stool or vomit
• High fever, severe abdominal pain or confusion
• Signs of dehydration such as very dark urine, dizziness or minimal urination

Simple ways to reduce the risk of food poisoning

• Clean and sanitise: Wash hands, and clean and sanitise chopping boards, knives and other equipment before and after food preparation.
• Separate: Keep raw meat, poultry and seafood away from ready-to-eat foods.
• Cook: Use a thermometer to check the internal temperature of foods such as meat. Most meats should reach at least 75 °C.
• Chill: Refrigerate leftovers within 2 hours and keep fridges at ≤4 °C.
• Check: Don’t taste-test suspicious food. Respect use-by dates and throw out food that smells or looks off.

If you work in hospitality, retail or care settings, structured training helps you prevent contamination and protect customers. Explore the Food Safety Supervisor course for a straightforward way to build confidence in safe food handling practices.

Frequently Asked Questions

How long do food poisoning symptoms last?

Many people recover in one to three days, but some food-borne illnesses can last longer depending on the pathogen and your health.

Is food poisoning contagious?

Some types are, especially norovirus. Wash hands thoroughly and clean high-touch surfaces to reduce spread.

Can reheated food make you sick?

Yes, if it wasn’t cooled quickly and reheated to steaming hot (≥75 °C). Bacteria multiply in the Temperature Danger Zone (5°C-60°C), so storing and reheating leftovers correctly is vital.

What should I drink when I’m sick from food poisoning?

Try oral rehydration solutions or water in small, frequent sips. Avoid alcohol and very sugary drinks until your condition improves.

When can I return to work after food poisoning? 

Food Handlers should be symptom-free for at least 48 hours before returning to food-related duties.