I was sick after eating a certain food, it must have been what made me sick

Symptoms of food poisoning, particularly vomiting, can occur within a short time after eating contaminated food. The last meal you ate may indeed have made you sick.

But it is also possible that the illness was due to a food eaten quite a long time before you became ill.

Onset of the first symptoms after consumption of the contaminated food is different according to the specific bugs (pathogens) that caused it. So consider all the foods eaten over the 3 days before symptoms first appeared.

Some bugs carried by food can also be passed person-to-person or from contaminated surfaces that people encounter in everyday life. The symptoms are the same and can start just as suddenly.

For a list of foods typically contaminated by particular pathogens and illness onset times see foodborne illness pathogens.



I got diarrhoea within a few hours after eating the contaminated food

Diarrhoea from a contaminated food does not usually start until at least 4-6 hours after eating that food but can be as much as 3 days after consumption.

Most bugs need time to multiply to harmful levels and travel through the digestive system.

If you experience diarrhoea in less than 4 hours from eating it is not likely to have been caused by the recent meal. Consider the previous meals or even food you ate the day before.



The food I brought up when I vomited must have caused the food poisoning

Food present in your vomit is not always an indication of the food that caused your illness. It is just the contents of the stomach at the time your first symptoms started. The food responsible for your illness may have been eaten a day or so before the symptoms appeared.



I was sick after eating so it must be food poisoning

Sometimes gastrointestinal illness that was not caused by food is mistaken for food poisoning. While food can be the cause of gastrointestinal illness it is not the only cause:

contaminated water including swimming pools used by adults and children with very recent gastro illness can cause similar symptoms

viral illnesses are easily passed person-to-person are also a common cause and can be contracted from family, friends and contact with others that have had very recent gastro-type illness.+

Good hand washing and personal hygiene can help reduce the risk of both person-to-person and foodborne spread of viral illness.



The food must have made me sick because it smelt or tasted bad

It is a common misconception that for food to make a person sick it must look, taste or smell bad, or be off.

Food ageing and spoilage are commonly caused by different organisms than is food poisoning. They may exist together, but not necessarily.

Most food poisoning bacteria do not cause food to look, smell or taste ‘bad’. So food which seems normal in appearance, taste and odour, can have enough harmful bugs to make someone ill.

Of course if food looks, smells or tastes ‘bad’ don’t eat it.

If in doubt about the condition of the food don’t eat it and throw it out.



Why are carrots always brought up when you vomit?

Actually, they are not carrots but lumps of orange-coloured bile.

Bile is a fluid made by the liver that helps digest fat, so it is commonly present.