Why does food poisoning cause nausea?

Nausea is a very common presentation of Food Poisoning. Inflammation and toxins can stimulate nerves in the digestive tract and the part of the brain that coordinates vomiting. You may feel queasy, have excess saliva, lose your appetite or notice that smells and movement worsen the sensation. Vomiting, diarrhoea and abdominal cramps may occur as well.

Nausea can also come from many non-food causes, including migraine, medicines, pregnancy and other infections. The symptom should be considered alongside its timing, associated symptoms and your health history.

Take small, regular sips of water or oral rehydration drink rather than forcing a large drink. When liquids stay down, try small amounts of plain food and avoid rich, greasy or strongly scented meals until you feel better. Rest in a comfortable position and move slowly if motion makes nausea worse. A pharmacist can advise whether an anti-nausea medicine is suitable for you, including if you are pregnant or take regular medication.

Get urgent care if vomiting prevents you from keeping fluids down, or if you have confusion, fainting, severe abdominal pain, blood or black material in vomit or stools, difficulty breathing, or signs of dehydration such as very little urine. Seek medical advice if nausea persists, keeps returning, or occurs with concerning symptoms such as severe headache or chest pain. Children, older adults, pregnant people and people with weakened immunity may need earlier assessment.

Tell the clinician what you ate before symptoms, when nausea started, whether you have vomited and how much fluid you can keep down. Ask about safe fluid choices, medicines to avoid and signs that mean you should return for care.