What actions to take in the event of food poisoning

Food poisoning leaves thousands of Canadians in a bad way each year. Find out what you can do to limit the damage.

Food poisoning: who's to blame?

People sometimes mistakenly believe that food poisoning is caused by overeating. In fact, this is completely false. Food poisoning is caused by the ingestion of food or beverages contaminated by microorganisms (viruses, bacteria, parasites, mould, and algae) or their toxins. It is true; however, that after a copious or spicy meal accompanied by flowing glasses of alcohol, this may trigger symptoms resembling those of food poisoning.

There are several routes of contamination possible, for example:

  • food manipulated or prepared by an infected individual
  • inadequate cleaning or undercooked food
  • food contact with an object (work surface, utensils, dishes, etc.) that has been contaminated by other foods

The causes of food poisoning

Here are some examples of common causes of food poisoning:

  • Norovirus. This virus is among the most common causes of gastroenteritis.

  • Salmonella. Salmonella, a bacteria sometimes found in raw or undercooked foods (poultry, meat, seafood, eggs, vegetables, fruits, etc.), is among the most common causes of food poisoning in Canada. Infection by this bacteria is called salmonellosis.
  • E. Coli. Naturally present in the intestines of humans and animals, the bacteria Escherichia Coli usually does not cause any problems. However, some strains (E. coli O157: H7) can make people very ill.
  • Listeria. This bacteria causes an infection called listeriosis. It can be found in milk and certain cheeses (especially non-pasteurized), smoked fish and ready-to-eat meats (pâtés, cold cuts, hotdog franks, etc.).

Travellers' diarrhea is a good example of food poisoning often due to the ingestion of foods or drinks contaminated by various viruses, bacteria or parasites.

Food poisoning contracted in exotic countries can occur during travel, upon returning or in the weeks that follow.

The causes of food poisoning

The symptoms of food poisoning

Here are the most common symptoms of food poisoning:

  • nausea
  • vomiting
  • cramps and stomach aches
  • diarrhea, sometimes bloody
  • feeling of general malaise
  • fatigue, and
  • fever

These symptoms are sometimes, but rarely, accompanied, by lightheadedness, dizziness, blurred vision or other nervous system-related manifestations.

Symptoms can occur for a few hours, a few days or even for a few weeks after having ingested the contaminated food.

The symptoms of food poisoning

How to recover

If food poisoning occurs, things often resolve themselves with time. Here are a few measures that can help you recover your health more quickly.

  • Rest. Get adequate sleep.
  • Stay well-hydrated and drink plenty of fluids, ideally water.
  • If you are experiencing diarrhea or significant vomiting, consider using a rehydration solution. These types of products are available at the pharmacy in the form of a liquid, powder to be reconstituted or frozen pops.
  • Consult a healthcare professional to know what foods and drinks you should avoid or what foods to favour.

The treatment of food poisoning usually consists of easing symptoms. For example, the following may be used:

  • acetaminophen, for fever or general malaise
  • an antinausea agent, for nausea or vomiting
  • an antidiarrheal, for diarrhea
  • an antispasmodic, for abdominal cramps

Over-the-counter medication should never be taken without first speaking to a healthcare professional, such as a doctor or pharmacist, since this can sometimes compromise recovery.

Medical treatments can be prescribed depending on the cause of food poisoning (drugs, intravenous rehydration, etc.). If food poisoning is caused by a bacterial infection, an antibiotic will be prescribed. Furthermore, food poisoning caused by a parasite often requires a medical treatment. In more serious cases, hospitalization may be necessary. 

When to consult

Although food poisoning is usually minor and transient, it is better to see a doctor if:

  • the affected individual is a child or an elderly person
  • symptoms are severe (e.g. violent abdominal cramps) or lasting more than 36 to 48 hours
  • you are unable to drink or eat
  • you present signs or symptoms of dehydration
  • you notice the presence of blood in your vomit or stools
  • you have a high fever (higher than 38°C or 100.4°F)

Speak to your pharmacist for additional information about food poisoning.


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What actions to take in the event of food poisoning

Each year, food poisoning causes grief for thousands of Canadians. Find out what you can do to limit the damage.
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