Food poisoning is an illness caused by bacterium such as salmonella and campylobacter.
The symptoms include nausea, vomiting, diarrhoea or abdominal pain.
Food-borne diseases including viruses are similar to food poisoning and have similar symptoms.
It can take time for the infection to develop inside the gut (typically 12-36 hours), so it may be caused by food eaten the day before or several days ago.