Is it a Stomach Virus or Food Poisoning?

When you are vomiting every hour or going through a bad round of diarrhea, you may not care that much whether you have a stomach virus or food poisoning. However, once you recover you may wonder if you can safely return to your favorite restaurant or barbecue stand again…so it can be valuable to know the difference.

In the United States, the most common cause of a stomach virus (also known as stomach flu) is the norovirus. This is a viral infection that attacks the digestive system (and has nothing to do with the flu virus). Stomach viruses like the norovirus are very contagious and can spread quickly. We’ve all heard the stories about passengers on cruise ships suffering en masse with the norovirus. Unfortunately, people infected with a stomach virus are contagious from the moment they become ill to at least the first few days after they recover. Typical stomach viruses can be spread in a number of ways:

  • Eating food or drinking liquids that have been contaminated with the virus
  • Touching a surface that someone with the infection has touched
  • Having direct contact with someone that has the virus

Stomach viruses can be easily spread through the vomit and stool of infected people, so caretakers should be especially careful and take precautions. Although there are rapid stool tests that can be used to detect the norovirus or rotavirus, your doctor will probably make a diagnosis by asking about your symptoms. Typical symptoms of a stomach virus (also known as gastroenteritis) are:

  • Diarrhea that may be watery or bloody
  • Nausea or vomiting
  • Stomach cramps, muscle aches or weakness
  • A low-grade fever
  • Headaches, as well as light-headedness or dizziness

Food poisoning often causes similar symptoms to a stomach virus, which is why the two conditions often confused. However, food poisoning is caused by consuming food that is contaminated by bacteria, viruses, or parasites. Medical professionals often use the term gastroenteritis to describe both conditions.

The symptoms of food poisoning hit more quickly than those of a stomach virus. While symptoms of a stomach virus can take days to develop, food poisoning symptoms can appear very quickly – within six hours of eating a meal. Food poisoning is usually caused by bacteria. Salmonella and E. coli are two common types of bacteria linked to food poisoning. Usually food poisoning happens to more than one person at a time. (Everyone who eats the contaminated food becomes ill.) Salad greens, eggs, undercooked poultry, dairy products and seafood can easily cause food poisoning if they are not handled properly, whether at home or in a restaurant.

Although the symptoms are similar, there are some ways to tell the difference between the stomach flu and food poisoning.

  • Bloody diarrhea is more likely to be a symptom of food poisoning.
  • Projectile vomiting and stomach cramps are often caused by the norovirus, a type of stomach virus.
  • Stomach viruses take longer to develop but usually go away in about 24 to 28 hours after symptoms begin. Food poisoning often lasts longer.
  • Food poisoning usually affects more than one person and can often be traced to a particular source.
  • A stomach virus is more likely to cause a fever, headache and stomach pain.

Whether you have food poisoning or a stomach bug, the important thing to do is treat it properly. Here are some tips:

  • One of the most important things to do is stay hydrated. Throwing up and suffering from diarrhea means you are losing a lot of fluids. Take small sips of water or broth to stay hydrated. Fluids that contain electrolytes such as sports drinks or coconut water can also be helpful (avoid sugary drinks).
  • If you can safely keep fluids in your system, you can start to eat simple, easy-to digest foods such as toast, crackers, soup, rice and bread.
  • Get plenty of rest. It’s best to cancel any planned activities until you feel better.
  • Don’t take any anti-nausea or anti-diarrhea medication without consulting a medical provider first (some medications can make you feel worse). Adults can take ibuprofen or acetaminophen to relieve symptoms.

Be sure to call your doctor if you have a fever, can’t tolerate liquids, have bloody stools or if your diarrhea is severe or lasts more than three days. If you take a prescription medication for a pre-existing condition but can’t keep it down, you should also contact your doctor.

23 Responses

Stay in touch with the conversation, subscribe to the RSS feed for comments on this post.

  1. Posted by LILY W.

    Hi I have a question though:

    I ate a meal at a restaurant, and 2-3 hours later began to aggressively vomit, which lasted for over an hour. I became super dizzy, tired and weak and could barely get up. I immediately fell asleep, and when i woke up i felt so tired/weak/and had a crazy head ache. Drinking was tough and anything other than simple bread/crackers was difficult to eat & made me nauseated.

    I was thinking it was food poisoning – but what does this sound like to everyone else?

    September 5, 2020 11:57 am Reply
  2. Posted by Phillip Elliott

    I have stomach pain low grade fever diahrea for two days. I think I have stomach virus or is covid.

    June 30, 2020 12:30 pm Reply
    • Posted by Reliant Medical Group

      Those could be symptoms of COVID-19, so it’s best to call your doctor about your symptoms.

      July 6, 2020 8:45 am Reply
  3. Posted by Kimberly

    Nobody has mentioned that some of these symptoms showing up after eating more greasy foods can cause gall bladder reactions or an abundance of liver bile. It isn’t always a virus or bacteria.

    February 11, 2020 7:03 pm Reply
    • Posted by Abigail

      Pls have been struggling and suffering from
      vomiting,running stomach, headache, waist pains, chills,nausea, farting,
      severe muscle pains and weakness
      Its all started when i finished eating pineapple and indomie at night. Pls i really need to know if it’s food poisoning that result to this illness??? Honestly I’m dying slowly for the past two months now…

      July 4, 2020 8:55 am Reply
      • Posted by Reliant Medical Group

        Definitely contact your primary care doctor about these symptoms!

        July 6, 2020 8:44 am
  4. Posted by Claudia

    After i ate market soup from the deli section few hours later the runs which I’ve had now off and on for 2 days. Last episode included blood. Day before this happened I had the flu shot o.j. t. So is it the flu shot or food poisoning.

    December 22, 2019 8:44 am Reply
    • Posted by Reliant Medical Group

      The flu shot should not cause these symptoms.

      December 26, 2019 9:24 am Reply
  5. Posted by A M

    Hello, i have been suffering from bouts of nausea (but no vomiting, strangely) for about three days. Just before the first episode, I ate two slices of greasy pizza that might have been bad. The next day I felt mostly fine, but when I ate lunch (also greasy, if there’s a connection) it came back worse than ever, for hours. At times I tried throwing up to make the nausea stop, but I could never do it. The next day I was fine, but had no appetite and felt uncomfortable after eating one slice of bread. I got diarrhea the next day, and bad stomach cramps the next. I am so sick of this. I am a hs student with a lot of homework and it sucks doing it while sick.

    September 12, 2019 7:00 am Reply
    • Posted by Maryin

      This sounds very similar to symptoms I’m having…. how did it turn out? Did you see a doctor? Any insight would be helpful.

      December 25, 2019 2:20 pm Reply
    • Posted by Ashley Berryman

      Staph bacteria are everywhere and many produce a toxin that is a top cause for food poisoning. Unlike other bacteria involving food illness, staph actually makes your food poisonous if it is left out too long in temperatures above 37 degrees, and it has a high salt-tolerance. When left out for 2 hours, consider food poisonous because staph toxins have begun to get high enough to get dang sick! Re-heating does NOT get rid of poison! Pizza may have staph toxin bud. 2 hours or toss it-always!

      December 26, 2019 11:32 am Reply
  6. Posted by Corina Wilson

    I became sick 8 hours after eating a crepe from a restaurant. It started as severe stomach cramps then the chills then started throwing up. I was up and down all night throwing up but no diarrhea even thou it feels like I have to. I’m sure it’s probably food poisoning.

    September 5, 2019 1:39 pm Reply
  7. Posted by Julie

    I’m constantly getting stomach viruses. Have been for years. Better during summer. Don’t know why unless stress related. It’s like my immune system is low. Can’t take herbs with medicines. Any ideas what could be causing this? Symptoms vary each time. Usually nausea, vomiting, diarrhea, fatigue, achy.

    April 25, 2019 7:24 pm Reply
    • Posted by Reliant Medical Group

      You should definitely consult your primary care provider about this, Julie.

      April 26, 2019 9:38 am Reply
    • Posted by V

      Please be seen by doctor… my mother thought she had stomach viruses constantly and it turned out to be lymphoma. Insist on Medical test for an accurate answer!

      December 9, 2019 5:05 pm Reply
      • Posted by Kay

        Eat in more and lower your risks maybe just try cereal in the morning, a sandwhich mid day, and good easy meal at night. Pedialyte to replace your fluids. My immune system has gotten so low this year. I’ve been out of the loop on germs so long, I guess they’ve gotten stronger. I have been getting sick more than usual. Nothing else wrong though internally. I’m also lactose intolerant and a lot of people are there days. Try narrowing in on that as well. My symptoms take a day or so to come into play, but I get a headache pretty fast. I dare not touch ice cream or I can kiss a night of sleep goodbye. Hope this helps.

        June 5, 2020 6:11 pm
  8. Posted by Cindy

    Hi. I have never had food poisoning before, and my husband ate the same thing as I did, except for frozen waffles about 8 hours prior. I have had a queasy stomach for a few days and all of a sudden after dinner I got bad stomach cramps, diarrhea, and burning up. I was so dizzy and my head started throbbing. I did throw up 3 times. Then I went to bed and was cold, and back up every 15 minutes with the same thing for another hour. Now, 3 hours later, I have a low grade fever of 99.3 and a really sore stomach. I am trying some crackers and herbal tea and water. Hope it doesn’t come back.
    PS. I do work at a daycare.

    March 30, 2019 11:39 pm Reply
  9. Posted by Ashleigh p

    Hello, I had sever vomiting and diarrhoea 7 days ago for about 15 hours – every ten to thirty minutes, and I could keep nothing down, low grade fever, joint aches, stomach cramps. It took the whole week off work as I was exhausted and joints were still aching – I’m al 15 weeks pregnant.

    Tonight 7 days after my 1st episode I have started to feel sick again. Is it possible to become re infected with the same bug? As I’m pregnant and my immunity is low.

    Do you think the original sickness was food poisoning or a stomach bug?

    I have been sent for listeria and salmonella testing, I am just awaiting the results.

    March 8, 2019 10:52 am Reply
    • Posted by Reliant Medical Group

      Based on your description, it sounds like it is likelier that you have a stomach virus. Of course, it’s difficult to tell for sure, so we are glad that you have consulted a doctor about your symptoms.

      March 12, 2019 9:04 am Reply
    • Posted by Emerson C

      I woke up with an upset stomach went to work and was in the restroom every 1hr. I completed the day at work it was a tuesday and took the whole week off. It got worse when i was at home i wasnt able to eat anything. I read to stay hydrated with sports drinks or any drink with electrolytes and so i did. I started feeling really cold and weak. I was in bed resting more than usual. It got a little better then i got a fever and felt like i wanted to puke but didnt. I woke up every 1hr to go to the restroom later i had a really heavy headache. Woke up same loose stool as usual. Now is a thursday i am feeling a little better now i can eat a little more but my stool is till loose my throat hurts too. I hope it can only last until sunday i dont want to keep missing work. Was it a good idea to stay home and let my body fight the norovirus or i should have visited a Dr ? ?

      June 20, 2019 10:19 pm Reply
      • Posted by Reliant Medical Group

        If this lasts more than three days, we suggest seeing a doctor.

        June 21, 2019 9:39 am
  10. Posted by Erica Bagby

    If I have I eaten something that mad me have diarrhea my only symptom can others get it. I have also gotten medicine

    February 22, 2019 5:33 pm Reply
    • Posted by Reliant Medical Group

      Hi Erica. Hope you are feeling better. As the article explains, if you contracted a stomach virus you would be contagious until the first few days after you recover. If it is food poisoning that caused your illness, people around you would only become sick if they also ate the same contaminated food that you did.

      February 25, 2019 10:31 am Reply

Some HTML is OK


Am I eligible to use Virtual ReadyMED?

Are you or the patient 4+ years old?
Are you in Massachusetts at time of video visit?
Do you have a Reliant PCP?
Do you have access to email on the device you are using?
By continuing I’m giving Reliant permission to communicate with me via text or email to complete this visit.

Am I eligible to use Virtual ReadyMED?

Do you have a MyChart account?