How Long Does the Stomach Flu Usually Last? A Timeline - GoodRx (2024)

The stomach flu can hit you anytime, any place. Unlike “the flu” — a respiratory illness caused by the influenza virus — the stomach flu viruses cause vomiting and diarrhea. The symptoms are uncomfortable and can be quite miserable.

Luckily, the stomach flu only lasts for a short period of time. Still, knowing what to expect and how to recover can make those days a little easier.

What are the symptoms of the stomach flu (gastroenteritis)?

The technical name for the stomach flu is viral gastroenteritis. It happens when a virus infects the gut and causes vomiting and diarrhea.

Symptoms come on suddenly. And they tend to follow a typical pattern:

• At first, you may have chills, fever, and nausea.

• Within hours to a day, you will develop vomiting and diarrhea.

• Stomach cramping, not wanting to eat, and body aches are common stomach flu symptoms as well.

The stomach flu spreads in environments where lots of people are close together, such as childcare centers and cruise ships. The incubation period is the time between when you get exposed to the virus and when you start having symptoms. With the stomach flu, it’s about 24 to 48 hours. So, it may seem like a domino effect as a few new people get sick each day as the virus is passed around.

The most common viruses that cause the stomach flu are norovirus and rotavirus:

• Norovirus is a very contagious virus and is the number-one cause of vomiting and diarrhea in the U.S. You can get norovirus by eating contaminated food, drinking contaminated water, or touching surfaces or objects that have the virus and then putting your fingers in your mouth.

• Rotavirus is also very contagious and causes diarrhea. It is the most common cause of diarrhea in infants and young children worldwide. Thankfully, there is a vaccine that protects infants and young children from getting gastroenteritis from rotavirus.

Stomach flu vs. food poisoning

The stomach flu is different from food poisoning. Though they have similar symptoms, food poisoning does not usually cause a fever. And instead of a virus, food poisoning is usually caused by bacteria.

Think about the potato salad that is left in the hot sun at a picnic. The warm temperatures over a few hours make potato salad a good environment for the growth of bacteria. And if you eat the potato salad that has grown bacteria, you will know in just a few hours that your gut is not happy. Food poisoning symptoms start more quickly after exposure than the stomach flu — usually 2 to 6 hours after eating food that has bacteria.

How long does the stomach flu usually last?

Luckily, stomach flu symptoms tend to go away as quickly as they come on. Typically, vomiting and diarrhea only last for 1 to 3 days. While you will start feeling better in just a few days, you may be tired and weak for a bit longer. This is because the vomiting and diarrhea can make you pretty dehydrated, causing your body to need a bit more time to fully recover.

How long is the stomach flu contagious?

The stomach flu is easily spread from one person to another by the fecal-oral route. This is just what it sounds like. Your hands get contaminated, and then you touch something that goes into your mouth. That is how the stomach flu is passed around.

You can spread the virus to another person as soon as you have symptoms. You can keep shedding the virus in your poop for a week or longer. So, even though you might feel OK after a few days, you can still get other people sick if you don’t wash your hands well after using the bathroom. The best way to limit the spread of the stomach flu is to wash your hands properly and to clean frequently touched surfaces.

What can you eat and drink when you have the stomach flu?

The most important thing to do when you have the stomach flu is to stay hydrated. Vomiting and diarrhea cause a loss of fluids as well as electrolytes. You can replace your lost fluids and electrolytes with liquids such as:

• Water

• Fruit juices

• Sports drinks

• Soup broths

Start by taking sips of clear liquids, such as water and broths. This helps to make sure your stomach is ready to handle fluids. Go slow and be patient. If a liquid causes you to feel nauseous and vomit, try sucking on ice chips.

You might not have much of an appetite with the stomach flu. This usually only lasts a short period of time, so the first focus should be on staying hydrated. Once your appetite returns, it is OK to start eating again. While there is no specific diet recommended for the stomach flu, there are some things that make diarrhea and vomiting worse. These include:

• Caffeine

• High-fat foods

• Foods with lots of simple sugars

• Dairy products

What is the treatment for the stomach flu?

There is no medicine that treats the stomach flu. There are some medications that can treat nausea and vomiting, like ondansetron (Zofran). But drugs that stop diarrhea can cause more harm than good if you have the stomach flu. Be sure to talk to your healthcare provider before starting any over-the-counter (OTC) antidiarrheal medicine.

Your provider may recommend probiotics to shorten the course of illness — and repair your gut from the damage caused by the virus. You can get many probiotics OTC in pills, powders, liquids, and other forms. Probiotics are also found in many foods such as kefir, yogurt, and kimchi.

When should you see a doctor for the stomach flu?

You should call your healthcare provider if you have vomiting and diarrhea for more than 3 days — especially if your symptoms are getting worse. They can make sure that you aren’t sick with anything else, such as a bacterial infection that needs antibiotics.

You also need to check in with your provider if you start showing signs of more serious dehydration. This could mean that you need to get fluids into your body through a vein, known as IV (intravenous) fluids. Signs of more severe dehydration include:

• Fast heart beat

• Breathing quickly

• Feeling dizzy

• Extreme fatigue

• Not being able to think straight

• Confusion