Someone experiencing stomach flu symptoms.

How to Tell the Difference Between Food Poisoning and the Stomach Flu

Food Poisoning vs Stomach Flu

Neither food poisoning or the stomach flu is a pleasant illness to get, but it is important to know the difference between the two and how to treat them. Sometimes it is hard to tell whether you are experiencing food poisoning vs stomach flu.

Both food poisoning and stomach flu are used quite interchangeably when commonly referred to, as we often are not sure which of the two we have. However, as you will see, there are some differences between the two. The most obvious difference is the length of time that the illness lasts and knowing this can help you with treatment.

What is Food Poisoning?

Caused by various bacteria, the severity of the food poisoning and the length of time it takes to show symptoms will depend on which of the bacteria that has been ingested.

Food poisoning is caused by eating food or drinking substances that have been contaminated with one of the bacteria that can cause food poisoning, such as vibrio or listeria. These foods can be anything from herbs and fruit and vegetables, to undercooked meat or meat being prepared on contaminated surfaces.

Food Poisoning Symptoms

Symptoms of food poisoning can show up as quickly as 30 minutes after ingesting the bacteria, but can also take as long as four weeks in the case of listeria. In fact, some cases of listeria have been documented to start showing symptoms after 70 days. A listeriosis outbreak in South Africa lasted from 2017 to 2018 and claimed over 180 lives. 27% of those were caused by contaminated meat products.

Food poisoning caused by staphylococcus aureus (also called staph) acts quickly in the body and can cause symptoms only 30 minutes after contaminated food has been eaten.

The norovirus can also cause food poisoning, with symptoms starting 12 to 48 hours after ingestion.

The most common symptoms of food poisoning include:

  • Nausea
  • Vomiting
  • Diarrhea that may contain blood or mucus
  • Stomach cramps and abdominal pain
  • A lack of energy as well as weakness (this can be made worse if dehydration is not treated)
  • A loss of appetite
  • A high fever
  • Aching muscles
  • Chills (feeling very cold while also having a fever)

Food Poisoning Treatment

Food poisoning can usually be treated quite easily at home and a visit to a clinic is unnecessary because food poisoning usually passes on its own. If it persists, seek a doctor. Here are some tips to help treat the symptoms:

  • Water and oral rehydration solutions. These are usually found in a powder form that is mixed with water. It should be consumed as much as possible, even if only sipping is possible. Rehydration solutions are available from pharmacies.
  • Paracetamol or acetaminophen. This can be used for pain and fever.
  • Eating small, light and bland meals. This includes toast, bananas and rice. Avoid fizzy drinks and spicy or rich foods, as these can make you feel even worse.
  • Antibiotics. These are only prescribed in specific cases where the person’s immune system is compromised or they are vulnerable.
  • Anti-nausea medication. You may be prescribed medication to lessen the nausea and stop, or at least lessen, the vomiting (anti-emetics).
  • Rest. Rest gives your body the ability to fight the bacteria easier and quicker. You should rest as much as possible.

When to Seek Medical Help

You need to get medical help for your food poisoning in the following instances:

  • If it is a baby or young child that have contracted food poisoning
  • If it is someone with a compromised immune system that has contracted food poisoning
  • If the person is pregnant
  • Bloody diarrhea
  • A high fever of over 102F
  • Frequent vomiting so that even liquids cannot be kept down
  • Signs of dehydration, including little or no urination, a very dry mouth and throat, being dizzy
  • Diarrhea that lasts more than three days.

What is the Stomach Flu?

Cause by a number of different viruses including norovirus and rotavirus, stomach flu is not technically a flu because it is not caused by the influenza virus. The stomach flu is called viral gastroenteritis (often shortened to just “gastro”).

This intestinal infection attacks the stomach and intestines. It is highly contagious and can develop after contact with an infected person or consuming contaminated food or water.

Symptoms usually appear within one to three days of infection and, like food poisoning, can range from mild to severe. The symptoms of stomach flu last for three to seven days. However, in severe cases, the symptoms can last up to 10 days. Because the infection is so contagious, anyone suffering from it should not go to school or work until two days after the symptoms have stopped.

Stomach Flu Symptoms

The symptoms of stomach flu include:

  • Watery diarrhea
  • Stomach cramps and pain
  • Nausea or vomiting
  • A low-grade fever
  • Muscle aches or a headache

Stomach Flu Treatment

Because the stomach flu is caused by a virus, antibiotics cannot be used to treat it. However, the symptoms can be treated as follows:

  • Paracetamol/acetaminophen. This can be used for pain and fever.
  • Anti-emetics. This can help with nausea and may be prescribed.
  • An over the counter anti-diarrheal medication. Like subsalicylate (Pepto-Bismol) or loperamide hydrochloride (Imodium), it can also be used if necessary.
  • Staying hydrated. This is also very important and, like food poisoning, water and oral rehydration solutions should be taken to avoid getting dehydrated.
  • Eat small, bland meals. Do not eat normal, solid or heavy foods as your body will not be able to keep them down.

When to Seek Medical Help for the Stomach Flu

Although it is usually treated at home and with over the counter medications, there are times when you should seek medical help. This includes:

  • If it is a baby or young child that have contracted stomach flu
  • If it is someone with a compromised immune system that have contracted stomach flu
  • If the person is pregnant
  • Blood in diarrhea
  • Vomiting blood
  • Unable to keep liquids down for 24 hours or longer
  • Dehydrated (very dry mouth and throat, little or no urine, dizziness)
  • Fever over 102F.

If your child or baby has the stomach flu, it is imperative to see a medical practitioner immediately if:

  • Their vomiting has lasted for several hours
  • They have bloody stool or severe diarrhea
  • They have a sunken fontanel (soft spot) on the top of their head
  • They have a dry mouth or cries without tears
  • Is unusually sleepy, drowsy or unresponsive


Both food poisoning and the stomach flu can be prevented through good hygiene habits like washing your hands with soap and water after visiting the bathroom, changing your baby, before and after working with food, and before eating. Food, especially meat should not be undercooked. We hope this has helped you in knowing whether you are experiencing food poisoning vs stomach flu.

Article Resources