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Symptoms of Food Poisoning

Experiencing These Symptoms Could Be a Sign of Food Poisoning


Woman sitting on bed holding stomach, head bowed
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Food Poisoning Symptoms

The symptoms of food poisoning can vary depending on what sort of bug you might be dealing with, but there are definitely some characteristic signs that show up in most cases.

For example, Salmonella poisoning, the most common type of food poisoning in America, features abdominal cramps, headache, nausea, fever, diarrhea and vomiting. These symptoms are quite general, and are likely to be present in pretty much every form of food poisoning you can think of. Moreover, while you're in the throes of sickness, you may not be in the frame of mind to make a fine distinction between abdominal cramps and abdominal pain.

Food Poisoning or Flu?

Also, you might wonder whether the symptoms you're experiencing are really signs of food poisoning, or whether it's merely some sort of stomach flu or stomach bug. In reality, though, the terms “stomach flu” or “stomach bug” are just expressions used to describe symptoms that are, for the most part, caused by food poisoning. In other words, if you have the stomach flu or a stomach bug, you probably got it by eating something that gave you a case of food poisoning.

For that reason, simply looking at symptoms isn't always enough to diagnose a case of food poisoning. You might also want to think about what you recently ate and where you ate it. For example, many people tend to feel a little queasy after their Thanksgiving dinner. It's easy to attribute that to having eaten too much, when in reality it may be a case of Salmonella poisoning.

So, if someone else who ate the same food also has the same symptoms, that's a strong indicator of a case of food poisoning.

This is an important point, because the question of whether it's a “stomach bug” or food poisoning may seem like a matter of semantics. But it's actually crucial to know, because if you ate contaminated food, you're going to want to know about it so no one else in your household eats the same food. Alternately, if you got food poisoning from a restaurant, that could be a major public health hazard and it would be important for the local health department to know about it.

Note that there's one special form of food poisoning, with its own unique set of symptoms and conditions, that we'll get to at the end of this article. Here, then, are some of the most common food poisoning symptoms, and some of their most likely causes:


Vomiting is one of the most common signs of food poisoning. This makes sense, because if you ate something bad, your body is going to try to get it out. Sending it back out the same way it came in is the best way to accomplish that.

Vomiting is one of the signs of food poisoning caused by the following bacteria:


Diarrhea is another common food poisoning symptom, and it's characteristic of the following bacteria:


Yes, even a headache can be a sign of food poisoning, but usually it will occur in combination with some of the other symptoms described here. Headache can be present in food poisoning caused by these bugs:
  • Salmonella
  • Listeria
  • Staphylococcus aureus (in severe cases)
  • Clostridium perfringens
  • Campylobacter jejuni

Abdominal Pain / Abdominal Cramping

Again, there's a pretty fine distinction to be made here, as it may not be so easy to isolate abdominal pain caused by cramping from some other type of abdominal pain. Nevertheless, this can be a symptom of some of these foodborne illnesses:
  • Salmonella
  • Shigella
  • Staphylococcus aureus
  • Clostridium perfringens
  • Campylobacter jejuni
  • E. coli (pain is severe)


Another very basic symptom and not so easy to quantify, nausea can range anywhere from a mild queasiness to vomiting and severe abdominal cramping. Like headache, it will likely present itself in conjunction with some of the other symptoms listed here. Nausea is among the signs of these kinds of food poisoning:
  • Salmonella
  • Shigella
  • Listeria
  • Staphylococcus aureus
  • Clostridium perfringens
  • Campylobacter jejuni


Because the bacteria that transmit the illness are generally (but not always) causing an infection, one of the most common symptoms of food poisoning is a fever, as seen in the cases caused by these bacteria:
  • Salmonella
  • Shigella
  • Listeria (fever can be quite persistent)
  • Campylobacter jejuni
  • E. coli (sometimes; can be mild)


Dehydration can be caused by vomiting and diarrhea, so it's another symptom that's difficult to distinguish on its own. Still, you may experience dehydration when suffering from any of these forms of food poisoning:
  • Salmonella (particularly in very young or very old people)
  • Shigella
  • Clostridium perfringens

Muscle Pain / Muscle Cramping

Another reason people sometimes mistake food poisoning for the flu is that the flu can cause muscle aches, and so can some forms of food poisoning, including:
  • Listeria (backache)
  • Staphylococcus aureus
  • Campylobacter jejuni

Botulism: A Special Case

Botulism is one of the most deadly forms of food poisoning, and it's caused by a bacteria that lives in an oxygen-free environment. This makes it different from other foodborne pathogens. Botulism also presents its own unique set of symptoms. You can see that they're quite different from the symptoms described above. Botulism symptoms include:
  • Fatigue / weakness
  • Dizziness
  • Double vision or blurred vision
  • Dry mouth
  • Difficulty swallowing or speaking
  • Paralysis (in extremely advanced cases)
Here's an article that goes into much more depth about botulism.
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