How Long Does Stomach Flu Last, and How Can You Treat It?

The stomach flu can hit you anytime, anywhere. Unlike “the flu” — a respiratory illness caused by the influenza virus — the stomach flu viruses cause vomiting and diarrhea. The symptoms are usually more than just uncomfortable: They 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’ll develop vomiting and diarrhea. 

• Stomach cramping, lack of appetite, 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 child care 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. 

How long does the stomach flu usually last?

The stomach flu is miserable, but usually it doesn’t last very long. Typically, vomiting and diarrhea only last for 1 to 3 days. Keep in mind that even though the worst of the symptoms may clear up in just a few days, you’ll likely feel tired and worn out for a bit longer. This is because vomiting and diarrhea can make you pretty dehydrated, and it can take several days for your body to fully recover.

What causes stomach flu?

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

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

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

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 probably won’t 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’s OK to start eating again. There’s no specific diet recommended for the stomach flu. However, some things tend to make diarrhea and vomiting worse, including:

• Caffeine

• High-fat foods

• Foods with lots of simple sugars

• Artificial sweeteners

• Dairy products

What is the treatment for the stomach flu?

There’s no specific medicine that treats the stomach flu. There are some medications that can treat nausea and vomiting, like ondansetron (Zofran). Some people who have uncontrollable vomiting for a prolonged period of time may need IV fluids to treat dehydration. But most people will recover at home without needing them.

Medications that stop diarrhea can cause more harm than good if you have the stomach flu. Be sure to talk to a healthcare professional before starting any over-the-counter (OTC) antidiarrheal medicine. 

Some healthcare professionals recommend probiotics to shorten the course of illness and to help 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.

How do you prevent the stomach flu?

To prevent the stomach flu, here are things you should do:

• Avoid physical contact with anyone who’s sick.

• Avoid visiting households (or spaces) when someone’s sick.

• Wash your hands frequently, particularly before eating. 

• If you share a household with someone who’s sick, be extra vigilant about hand washing and disinfect shared surfaces

• Follow safe practices for food preparation.

When should you see a doctor for the stomach flu?

You should see a healthcare professional 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 should also see a healthcare specialist if you start showing signs of more serious dehydration. This could mean that you need IV fluids. Signs of more severe dehydration include:

• Fast heart beat (over 100 beats per minute)

• Breathing quickly

• Extreme fatigue or weakness

• Feeling dizzy or like you’re going to pass out

• Not being able to think straight

• Confusion 

• Dark urine 

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Written by:

Angela Dunn, MD, MPH

Angela Dunn, MD, MPH, is a public health physician practicing in Utah, with a focus on serving under-resourced communities.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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