What should you know about effects of food poisoning?

Food poisoning follows eating or drinking something contaminated with an infectious organism or toxin. The gut may respond with diarrhoea, nausea, vomiting, cramping or abdominal pain; fever can occur when the immune system reacts. Food poisoning commonly presents with these digestive symptoms, but the exact pattern depends on the cause. Fluid and salts can be lost through repeated vomiting or loose stools, leading to dehydration.

Watch for thirst, a dry mouth, dizziness, unusual tiredness or passing urine less often. Young children, older adults, pregnant people and anyone with a long-term illness may become unwell more quickly and should have a lower threshold for advice.

Take frequent small sips of water or an oral rehydration solution, especially after vomiting or diarrhoea. Oral rehydration therapy replaces water and salts in a measured way. Rest, and eat small plain meals when you feel able; avoid alcohol and foods that clearly worsen symptoms. Wash hands with soap and water, avoid preparing food for others while ill, and clean contaminated surfaces. Do not use leftover antibiotics or anti-diarrhoeal medicines without advice, since the right choice depends on the cause and your symptoms.

Get urgent medical help for severe dehydration, fainting, confusion, severe or worsening abdominal pain, blood in vomit or stool, or inability to keep fluids down. Seek prompt advice for persistent fever, symptoms that are not settling, or illness after a high-risk food exposure. IV fluid therapy may be needed when dehydration is significant or drinking is not possible. A child, older adult or pregnant person with repeated vomiting or diarrhoea should be assessed early.

Ask whether your symptoms fit food poisoning or another illness, which fluids are suitable, and whether you need testing. Tell the clinician when symptoms began, what you ate, how often you have vomited or passed stool, whether there is blood or fever, and how much you are drinking and urinating. Ask when it is safe to return to work, school or food preparation.