Does food poisoning cause fever?

Food poisoning can inflame the digestive system and activate immune defences. Fever may appear with diarrhoea, stomach cramps, nausea or vomiting. Some foodborne illnesses cause digestive symptoms without fever, so its absence does not rule out food poisoning. A fever can also come from another infection, and the symptom alone cannot identify the cause.

Pay attention to the whole pattern: when symptoms began, whether other people who shared the food are ill, and whether you can keep fluids down. These details help a clinician assess the likely source and your risk of dehydration.

Rest and take frequent small sips of water or an oral rehydration drink. If nausea is present, small amounts may be easier than a full glass. When your appetite returns, choose simple foods and avoid alcohol, very fatty meals and foods that worsen diarrhoea. Check your temperature if you feel hot or chilled, and follow the label or a pharmacist's advice before taking a fever medicine, particularly if you are pregnant or have another medical condition.

Seek urgent medical help for confusion, fainting, severe weakness, trouble breathing, severe or worsening abdominal pain, blood in vomit or stool, or signs of serious dehydration such as very little urine. Contact a clinician promptly if fever is high or persistent, symptoms are getting worse, you cannot keep fluids down, or the sick person is a young child, older adult, pregnant, or immunocompromised.

Ask whether your symptoms fit food poisoning, how to replace lost fluids, which medicines are suitable for you, and what temperature or symptom change should prompt reassessment. Tell the clinician about recent meals, travel, medicines, and anyone else who became unwell.