What are Viral Gastroenteritis? Stomach Flu vs Food Poisoning

Food Poisoning Vs Stomach Flu
Medically reviewed by Dr. Mavra Farrukh


An upset stomach can affect physical health, emotional well-being, the flow of daily routine, and work. Nobody wants to go through the trouble of having a bathroom emergency every 10 minutes. However, it can only be treated by understanding the cause. Experiencing diarrhea, vomiting, stomach cramps, and nausea, it is difficult to tell apart whether it is a stomach bug, food poisoning, or anything else. Depending upon the cause, the treatment regime is designed. You can understand the symptoms by reading this article, but it is best to consult a doctor for a proper diagnosis.

What is stomach flu?

Stomach flu, also known as viral gastroenteritis, is caused by a virus that infects the intestines and stomach, causing inflammation and infection. However, the cause is not always a virus; bacteria or parasites sometimes cause the infection. Although the symptoms of both are similar, they include diarrhea, abdominal cramps, and nausea. It is difficult to differentiate between bacterial or viral infection as the symptoms are the same. Therefore, it is better to consult a doctor for the right diagnosis. 

Why is viral gastroenteritis called “stomach flu?”

Viral gastroenteritis is called stomach flu compared to the “flu” or influenza. Because both infections are caused by viruses, both are common during flu season, making you sick but affecting different body organs.

Suffering from diarrhea and abdominal cramps? Get treatment for viral gastroenteritis from our doctor

What is the difference between food poisoning and stomach flu?

It is important to understand the differences between food poisoning and stomach flu (viral gastroenteritis)l for proper diagnosis and treatment. Both conditions affect the digestive system but have different causes and symptom patterns.

  • Stomach Flu (Gastroenteritis): Stomach flu is caused by contagious viruses or bacteria that spread from person to person. Norovirus is the most common culprit.
  • Food Poisoning: Food poisoning is caused by consuming contaminated food or water. Bacteria like Campylobacter, Salmonella, E. coli, Listeria, and viruses like Norovirus can cause it.
Sr.DifferencesFood poisoningStomach flu
1.CausesBacteria (Campylobacter, Salmonella, E. coli, Listeria) or viruses (Norovirus)Viruses (most commonly Norovirus)
2.SymptomsMore likely to start with watery or bloody diarrheaMore likely to cause fever and vomiting
3.DurationIt can range from 24 hours to several weeks, depending on the bacteriaTypically lasts about 1 to 3 days
4.Incubation PeriodQuick onset, usually within hours after eating contaminated foodUsually, about 24 to 48 hours after exposure
5.TreatmentHydration with fluids, antibiotics in some casesHydration with fluids, anti-nausea medications

What are the symptoms of stomach infection?

Stomach infection can have various causes, from bacterial to viral or parasite infection. 

While commonly referred to as stomach flu, gastroenteritis differs from influenza, which affects only the respiratory system (nose, throat, and lungs). Gastroenteritis, on the other hand, impacts the intestines, leading to a distinct set of symptoms. Common symptoms of gastroenteritis include: 

  • Watery diarrhea: Usually non-bloody. Bloody diarrhea may indicate a more severe infection.
  • Nausea and vomiting: These are common and can occur separately or together.
  • Stomach cramps and pain: Intestinal inflammation often causes significant discomfort.
  • Occasional muscle aches or headaches: Although less common, they can accompany the infection.
  • Low-grade fever: A mild fever can occur as the body fights the infection.

Duration and onset:

  • Viral gastroenteritis symptoms: Typically appear within 1 to 3 days after infection.
  • Symptom duration: Usually lasts 1 to 2 days, but sometimes, they can extend up to 14 days.

Because the symptoms of viral gastroenteritis are similar to those caused by bacteria like Clostridioides difficile, Salmonella, and Escherichia coli, or parasites such as Giardia, it can be challenging to identify the exact cause without further medical evaluation.

Symptoms of food poisoning and stomach flu are similar Get the right diagnosis and treatment within minutes

What are the causes of stomach bug and food poisoning?

The cause of stomach bug (viral gastroenteritis) and food poisoning can be understood by distinguishing between these two common illnesses and managing their symptoms effectively:

Causes of stomach bug (Viral gastroenteritis)

Stomach bugs are primarily caused by highly contagious viruses that spread from person to person. The following viruses cause stomach bug infections more frequently:

  • Norovirus 60%
  • Adenovirus 10%
  • Astrovirus 2-9%
  • Rotavirus 25-65%

Stomach bugs caused by rotavirus or norovirus infections are especially contagious. In the United States, infections most commonly occur between October and April. The viruses can spread through direct contact with an infected person or by touching surfaces contaminated by the virus.

Causes of food poisoning

Food poisoning occurs when infectious organisms such as bacteria, viruses, or parasites contaminate food or water. Common bacterial causes include:

  • Staphylococcus aureus
  • Campylobacter
  • Salmonella
  • Listeria
  • E. coli

Viruses like norovirus can also contaminate food, leading to foodborne illness. Additionally, toxins produced by certain bacteria, such as Staphylococcus and Bacillus, can cause food poisoning even after the food has been cooked. Sources of contamination include: 

  • Unpasteurized beverages (e.g., milk, cider, juice)
  • Soft or unpasteurized cheeses (e.g., Brie, feta)
  • Contaminated or undercooked meat
  • Unwashed vegetables and fruits
  • Raw and undercooked eggs
  • Contaminated water
  • Raw fish or oysters
  • Undercooked rice
  • Raw sprouts

Food poisoning can affect anyone but is more common in babies, young children, and the elderly. Travelers to underdeveloped countries are at increased risk and should avoid undercooked foods and rely on bottled water.

Overlapping causes

There is some overlap between the causes of food poisoning and stomach flu, as some organisms can cause both. For example, norovirus can spread through contaminated food or directly from person to person. This overlap can complicate distinguishing between food poisoning and stomach flu based solely on symptoms.

Stomach virus can cause serious dehydration Timely diagnosis and treatment can prevent worsening infection

What kills the stomach virus?

There is no specific medical treatment for viral gastroenteritis, commonly known as the stomach flu. Antibiotics are ineffective against viruses. Instead, the focus is on self-care measures to alleviate symptoms and prevent dehydration.

Self-care tips

  1. Hydration: Drink plenty of liquids such as water, clear soda, clear broths, or non-caffeinated sports drinks. Oral rehydration solutions can also be beneficial. Suck on ice chips or take small sips of fluids frequently. Avoid alcohol, caffeine, and sugary drinks, as they can worsen dehydration.
  1. Diet: Avoid solid foods for a few hours for your stomach to settle. Gradually reintroduce bland, easy-to-digest foods like soda crackers, soup, oats, noodles, bananas, and rice. Avoid fatty, spicy, and highly seasoned foods until you feel better.
  1. Rest: Ensure plenty of rest as the illness and dehydration can cause weakness and fatigue.
  1. Medications: Adults may use over-the-counter anti-diarrheal medications like loperamide (Imodium A-D) or bismuth subsalicylate (Pepto-Bismol), but avoid these if you have bloody diarrhea or fever.

For Infants and Children

  • Hydration: Use oral rehydration solutions available at pharmacies. Avoid plain water and apple juice, as they don’t effectively replace lost electrolytes. Once rehydrated, return to a normal diet with toast, yogurt, fruits, and vegetables. For infants, continue breastfeeding or use formula after letting the stomach rest.
  • Avoid sugary foods: Avoid giving ice cream, sodas, and candy, as they can worsen diarrhea.
  • Rest: Ensure your child gets plenty of rest.
  • Medications: Avoid giving store-bought anti-diarrheal medications unless advised by a doctor.

Medical treatments

  • IV fluids for severe dehydration, especially in young children and the elderly.
  • Antiemetics medications like ondansetron, metoclopramide, or prochlorperazine can help reduce nausea and vomiting.
  • Antibiotics are used in specific cases of bacterial infections but are usually unnecessary for viral gastroenteritis.
  • Prescription medications may be required for severe cases, as a healthcare professional advises.
  • Over-the-counter medications include anti-diarrheal and anti-nausea medications.

By following these guidelines, you can effectively manage and recover from a stomach virus at home. However, always be vigilant about the severity and duration of symptoms and seek professional medical advice when necessary.

Diagnosis of food poisoning and stomach flu

Diagnosing food poisoning and stomach flu (viral gastroenteritis) involves a combination of a physical exam, a review of symptoms, and sometimes laboratory tests. Your healthcare provider will ask about your recent activities, food intake, and other factors to determine the cause of your symptoms.

For food poisoning

Medical history and symptoms: Your provider will ask about your symptoms, such as vomiting, diarrhea, stomach cramps, and fever. They will inquire about recent foods or drinks you’ve consumed, particularly any that may have been undercooked or improperly stored. If others who ate with you are also sick, this can help pinpoint a common source. Changes in medications or recent travel can provide clues about potential sources of infection.

Physical examination: The provider will check for signs of dehydration and other symptoms to rule out different illnesses. Vital signs like blood pressure, pulse, and temperature may be assessed.

Laboratory tests: Testing stool samples can identify specific bacteria, viruses, parasites, or toxins causing the illness. Also, blood tests may be conducted to find the cause of the illness, rule out other conditions, or identify complications. Determining the exact cause of food poisoning can be challenging, especially in isolated cases. Public health officials may be able to trace the source in large outbreaks.

For viral gastroenteritis (stomach flu)

Medical history: The doctor will ask about the type, duration, and frequency of symptoms such as nausea, vomiting, diarrhea, and abdominal pain. They will inquire if you’ve been in contact with others who are sick. Recent travel and any pre-existing conditions or medications you’re taking will be reviewed.

Physical Examination: Blood pressure and pulse are checked for signs of dehydration. The provider will look for fever, listen to abdominal sounds, and check for tenderness or pain.

Sometimes, a digital rectal exam may be performed to check for blood in the stool, which can indicate other conditions.

Stool Tests: You may be asked to provide a stool sample to detect signs of infection, inflammation, or other digestive diseases. Instructions will be given on how to collect and where to send the sample for analysis.

Is food poisoning contagious?

Food poisoning, also known as foodborne illness, can be caused by various bacteria, viruses, or parasites that contaminate food or beverages. Whether food poisoning is contagious depends on the specific causative agent:

Contagious causes

  • Bacterial and Viral Infections: Certain bacteria like Salmonella, Campylobacter, and Escherichia coli (E. coli), as well as viruses like Norovirus and Hepatitis A, can be contagious. These organisms can spread from person to person through direct contact with infected individuals or indirectly through contaminated surfaces, food, or water.
  • Parasitic Infections: Some parasites, such as Giardia and Cryptosporidium, can also be transmitted through contaminated food or water sources.

Non-Contagious causes

  • Chemical Toxins: Food poisoning caused by chemical toxins or toxins produced by bacteria (like Staphylococcus aureus) typically cannot spread from person to person. These toxins usually result from improper food handling or preparation rather than from an infectious agent.

How long is stomach flu contagious?

Stomach flu, or viral gastroenteritis, is highly contagious and can spread easily from person to person. The duration of contagiousness varies depending on the specific virus causing the infection:

Acute contagious phase

  • Symptomatic period: You are most contagious during the acute phase of the infection when you experience symptoms such as diarrhea, vomiting, nausea, and abdominal pain.
  • Immediate post-recovery: Contagiousness typically continues for a few days after symptoms have subsided.

Extended contagious period

You may sometimes remain contagious for up to two weeks after recovering from the illness. Even if you feel better and symptoms have resolved, the virus may still be present in your stool and potentially shed to others.

How to prevent stomach virus after exposure?

Preventing the spread of contagious foodborne illnesses like stomach flu (viral gastroenteritis) involves several key practices:

  • Wash hands thoroughly with soap and water frequently, especially after using the bathroom and before handling food or eating.
  • Do not share utensils, towels, or other personal items with individuals who are sick or have recently recovered from stomach flu.
  • Clean and disinfect surfaces that may have been contaminated with feces or vomit, especially in bathrooms and kitchens.
  • Cook food to safe temperatures to kill harmful bacteria and viruses.
  • Refrigerate perishable foods promptly.
  • Avoid cross-contamination between raw and cooked foods.
  • Antibiotics are ineffective against viruses, including those that cause stomach flu. They are only useful for treating bacterial infections.
  • Stay home from work, school, or public gatherings for at least a few days after symptoms subside to prevent spreading the virus to others. You are most contagious when experiencing symptoms and for a few days thereafter.
  • For infants, getting vaccinated against rotavirus starting at 2 months of age can help prevent severe stomach flu caused by this specific virus.

By adhering to these preventive measures, you can significantly reduce the risk of spreading stomach flu to others and promote a quicker recovery for yourself or your family members. If symptoms persist or worsen, seek medical advice promptly for appropriate management and care.

Food poisoning requires antibiotics for complete recovery. Get a prescription for the treatment of food poisoning online

What are the possible complications of stomach flu?

Both stomach flu (viral gastroenteritis) and food poisoning can lead to dehydration, especially if symptoms persist or are severe. Dehydration occurs when the body loses more fluids and electrolytes (such as sodium and potassium) than it takes in. This can happen due to excessive vomiting, diarrhea, or inadequate fluid intake during illness. Here are signs and symptoms to watch for:

  • Less frequent urination than usual.
  • Urine that appears darker in color than normal.
  • Feeling parched or having a dry sensation in the mouth or throat.
  • In infants, fewer wet diapers than usual.
  • Babies and toddlers may produce fewer tears when crying.
  • Heart beat faster than usual.
  • Blood pressure readings that are lower than normal.
  • Feeling unusually thirsty, even after drinking fluids.
  • Feeling dizzy, especially when standing up, may indicate low blood pressure.

Signs in babies

  • Sunken eyes or fontanels: Fontanels are the soft spots on a baby’s head. Sunken fontanels or eyes can indicate significant dehydration in infants.

Should I go to the doctor for stomach flu or food poisoning?

It’s crucial to seek medical attention if your fever exceeds 102°F or if you observe blood in your vomit or stool. These symptoms may indicate a more serious condition requiring medical evaluation and intervention. Additionally, if symptoms persist or worsen, especially in vulnerable populations such as infants, young children, older adults, or individuals with weakened immune systems, immediate medical attention can help prevent dehydration and other complications.

FAQs About Food Poisoning By Your Doctors Online Team

How long does food poisoning last?

Most patients with mild to moderate disease improve in a few hours to a few days. Severe disease may last a prolonged period of more than 10 to 14 days and may even require hospitalization and, if not treated on time, can even lead to complications like death.

Can a yeast infection cause stomach pain?

Yeast infections can lead to imbalances between good and bad bacteria, leading to early food digestion and bloating. This bloating and gas lead to belly pain.

Can tooth infection cause stomach pain?

Tooth or gum infection can create an imbalance in mouth bacteria; these bacteria travel down to the stomach and cause inflammation.

What drinks help food poisoning go away?

Food poisoning may cause symptoms like diarrhea and vomiting, which lead to dehydration and electrolyte imbalances. Oral rehydration solutions (ORS) and sports drinks with sugar and salt help replace lost fluid and electrolytes. 

Do vaccines help in Gastroenteritis?

Vaccines have been highly successful in reducing the global burden of rotavirus. They are recommended for infants older than six weeks but younger than two years; studies are underway to assess the safety and efficacy of starting vaccination in the newborn period.

What is the quickest way to get rid of a stomach bug?

To recover quickly, rest and staying well hydrated are recommended. If your tummy is still upset, frequent sips of water, sports drinks, broth, or juice can help. It is essential to know that water alone may not keep you hydrated in severe cases of diarrhea, so electrolyte hydration is required.

How do you tell if a stomach bug is viral or bacterial?

Generally, viral gastroenteritis produces milder symptoms that last a few days, including nausea, vomiting, or diarrhea. Conversely, bacterial gastroenteritis is associated with more intense symptoms like severe abdominal pain and can last longer than a week without treatment. A fever and chills may also accompany these symptoms.

How fast does food poisoning happen?

Mostly, the symptoms of food poisoning appear soon after eating contaminated food. However, they may start at any point between a few hours and several weeks later.

What can be mistaken for food poisoning?

It can be challenging to distinguish between food poisoning and gastroenteritis (often called the stomach bug) because they share similar symptoms caused by various bacteria or viruses. The same bacteria or viruses can live on food or humans, resulting in similar illnesses. Despite the differences, both conditions can manifest with similar symptom patterns, making it challenging for individuals to self-diagnose without medical testing.

What steps should I take after food poisoning?

After experiencing food poisoning, the primary focus should be replacing lost fluids and electrolytes. Drinking plenty of liquids is essential, even if vomiting occurs. Sipping small amounts of clear fluids can help prevent dehydration. Consuming saltine crackers can also aid in replacing lost electrolytes, supporting recovery from the illness.

Your Doctors Online uses high-quality and trustworthy sources to ensure content accuracy and reliability. We rely on peer-reviewed studies, academic research institutions and medical associations to provide up-to-date and evidence-based information to the users.

Get started today

Talk to online doctors now and get medical advice, online prescriptions, and referrals within minutes. On-demand healthcare services at your fingertips.

talk to online doctor 24/7 free

See a doctor now

Continue in Browser