Why does food poisoning cause fever?

Fever is a common presentation of Food Poisoning. Immune signals released during an infection can reset the body's temperature control, causing a high temperature, chills, sweating or feeling generally unwell. Fever may appear with diarrhoea, vomiting, nausea or abdominal cramps, although not everyone with food poisoning develops it.

A fever does not by itself show which germ is responsible. Respiratory infections, urinary infections and other illnesses can also raise temperature, so new symptoms elsewhere in the body are relevant when deciding whether to seek advice.

Drink regularly, rest and wear light, comfortable clothing. If vomiting or diarrhoea is present, use small frequent sips of water or oral rehydration drink. Follow the label and seek pharmacist advice before taking a fever medicine, particularly for children, pregnancy, liver disease or regular medicines. Keep an eye on how alert you feel and whether you are passing urine normally, as these can help identify dehydration.

Seek urgent medical help for confusion, difficulty breathing, a stiff neck, a widespread rash, fainting, inability to keep fluids down, severe abdominal pain, blood or black stools, or signs of dehydration. Arrange a medical review if fever persists or you are worried about its course, especially in a young child, older adult, pregnant person or someone with a weakened immune system. Describe any recent meals, travel and sick contacts.

Ask how to manage fluids and fever safely, which symptoms suggest you need reassessment, and whether your medical conditions or medicines change the plan. Note when the fever began and whether it follows meals or occurs with bowel symptoms.