What should you know about food poisoning and headache?

Vomiting and diarrhoea reduce the body's fluid and salt stores, which can contribute to headache, thirst, dizziness and tiredness. Fever and poor sleep can also make the head hurt. Headache is not specific to food poisoning, so its presence does not establish the cause. Consider the full pattern, including nausea, abdominal pain, fever and whether other people who ate the same food are ill.

A headache that began before the stomach symptoms, feels very different from usual, or continues after hydration improves may have another explanation. Food Poisoning and Nausea offer related information.

Rest in a cool, quiet place and take small, regular sips of water or oral rehydration solution. Restart fluids gradually after vomiting. Eat light food when able. Ask a pharmacist or clinician which pain reliever is suitable for you, particularly if you are dehydrated, pregnant, have kidney disease or take other medicines; avoid taking more than the label advises.

Track urine, alertness, fever, vomiting and headache severity. This helps show whether hydration is helping or whether the illness is changing.

Get emergency help for a sudden extreme headache, stiff neck, confusion, weakness on one side, trouble speaking, fainting, a seizure, breathing difficulty or inability to keep fluids down. Seek prompt assessment for worsening fever, blood in stool, severe abdominal pain, very little urine or a headache that remains severe despite rest and fluids.

Could dehydration explain my headache, and how should I replace fluid? Is my pain medicine suitable with my health conditions? Does the headache pattern suggest another cause? Do I need an examination or testing?