Stomach flu typically resolves on its own, but treatments that can help you recover include replenishing lost fluids and electrolytes to stay hydrated, getting plenty of rest, and using over-the-counter (OTC) medications like Imodium and Pepto-Bismol.

Different viruses can cause stomach flu, medically known as viral gastroenteritis. Stomach flu is highly contagious and has symptoms like diarrhea, vomiting, and abdominal pain. See a healthcare provider if your symptoms continue to worsen or you show signs of severe dehydration.

Read on to learn about stomach flu treatments and symptom management options, how to potentially prevent spreading it, and when to see a healthcare provider.

Viral gastroenteritis, commonly known as the “stomach flu,” is actually an infection of your intestines. The stomach flu (not a medically correct name) is a highly contagious illness that causes unpleasant symptoms like diarrhea, cramps, fever, nausea, and vomiting.

Viruses most commonly cause stomach flu. Despite the name, influenza viruses do not cause stomach flu. Instead, norovirus is the most common cause. Other viruses that cause the stomach flu include adenovirus, astrovirus, and rotavirus, which are more common in children than adults. Some bacteria, chemicals, and parasites may also cause symptoms.

Stomach flu symptoms vary in intensity from person to person. Common stomach flu symptoms include:

• Abdominal pain or cramping
• Fever
• Nausea or vomiting
• Watery diarrhea

People with stomach flu may get easily dehydrated. Dehydration symptoms include:

• Dark-colored urine
• Extreme thirst or dry mouth
• Fatigue or tiredness
• Light-headedness or fainting
• Sunken eyes
• Urinating less than usual

The stomach flu is acute, meaning it comes on suddenly, and it usually lasts less than a week. However, how long stomach flu lasts can depend on what virus causes it. Below are the most common viral causes of stomach flu and how long their symptoms typically last:

• Norovirus: Symptoms typically begin 12 to 48 hours after contact and last one to three days.
• Rotavirus: Symptoms typically begin two days after contact and last three to eight days.
• Adenovirus: Symptoms typically begin three to 10 days after contact and last one to two weeks.
• Astrovirus: Symptoms typically begin four to five days after contact and last one to four days.

How long you’re contagious can depend on what type of virus caused your stomach flu. The norovirus, which is highly contagious, can be found in your stool before you have symptoms and for up to two weeks after you start feeling better.

The viruses may spread through contact with infected stool or vomit. An infected person may spread viral particles by preparing drinks and foods, shaking hands, and touching objects without washing their hands. 

You may contract stomach flu viruses by consuming food or drinks made with contaminated water. Bacteria, chemicals, or parasites may infect food and cause food poisoning, a type of gastroenteritis. Swimming in contaminated water may increase your risk of the stomach flu.

The stomach flu is not always preventable, but you can significantly lower your risk by:

• Cleaning commonly touched objects and surfaces 
• Getting vaccinated (i.e., some vaccines protect infants against rotavirus)
• Properly washing your hands

Stomach flu typically gets better on its own without medical treatment. Certain treatments exist to help replace lost fluids and electrolytes and prevent dehydration. Other remedies may help alleviate symptoms and help you manage while you’re sick.

1. Drink Fluids

Focus on getting plenty of fluids. Dehydration can be a concern if you cannot replenish fluids and electrolytes like potassium and sodium. Severe dehydration from the stomach flu is most common in infants, children, older adults, and people with weak immune systems.

Adults with the stomach flu can replenish lost fluids by consuming liquids like:

Children, people with severe diarrhea and vomiting, and older adults with weak immune systems may require a rehydration solution containing electrolytes and glucose (sugar). Rehydration solutions include CeraLyte, Natrualyte, Infalyte, and Pedialyte.

2. Ease Into Eating

If you have the stomach flu, you might not feel like eating. As your symptoms start to alleviate, ease into eating. Eating salty, easy-to-digest foods like saltine crackers can help replace lost electrolytes like sodium and give you some energy. Bland foods that may quell nausea include clear broths or soups and oatmeal.

Eating bland foods for one or two days while treating your symptoms is typically safe but should not be continued for long periods of time. Once you start feeling better, make sure you gradually reintroduce a balanced diet of carbs, healthy fats, and lean proteins.

3. Avoid Certain Foods

Some foods may worsen stomach flu symptoms. For example, the bland diet advises against fried, high-fiber, spicy, and raw foods. Alcoholic and caffeinated beverages, including coffee, soft drinks, and tea, may also aggravate your symptoms.

Other foods that you might avoid until your symptoms resolve:

• Dairy products containing lactose
• Fermented foods (e.g., pickles and sauerkraut)
• High-fat foods (e.g., fast foods, fried foods, and pizza)
• High-fiber or raw vegetables (e.g., broccoli, cabbage, and corn)
• Sugary foods
• Whole grains, which often have a lot of fiber

4. Get Adequate Rest

Stomach flu symptoms generally resolve on their own with plenty of rest. Sleep supports your immune system by helping get rid of bacteria and reducing inflammation. In contrast, poor sleep may increase inflammation and worsen infectious illnesses like stomach flu.

5. Try Medications

Over-the-counter medications (OTC), including Imodium (loperamide) and Pepto-Bismol (bismuth subsalicylate), may help alleviate diarrhea. Do not give those medications to children or use them if you have blood diarrhea or a fever.

Imodium

Imodium helps treat diarrhea by slowing gut movement. You may develop mild side effects, such as constipation and fatigue. However, it may also cause severe side effects, like changes in heart rhythm, which can be life-threatening.

Do not take Imodium without consulting a healthcare provider if you have:

• An irregular or slow heartbeat
• Issue with fainting
• Low potassium levels

Do not use Imodium if you take amiodarone, which treats irregular heart rhythms, or methadone, an opioid. Imodium may adversely interact with those medications. Imodium may also be unsafe for children younger than 2.

Pepto-Bismol

Pepto-Bismol typically treats digestive symptoms like heartburn and indigestion. Pepto-Bismol may treat mild diarrhea symptoms by reducing the severity of gas and nausea.

Pepto-Bismol alleviates diarrhea by:

• Boosting electrolyte and fluid reabsorption
• Decreasing inflammation in your gut
• Preventing bacteria from binding and growing on the walls of your stomach
• Reducing intestinal secretion

Pepto-Bismol is safe for most people if used correctly. Some people may develop minor side effects like black poop or nausea, which usually goes away once you stop taking the medication.

Do not take Pepto-Bismol if you are pregnant or breastfeeding, have an allergy to the ingredients, or have diabetes or gout. Speak with a healthcare provider if you are unsure whether Pepto-Bismol is safe for you and before giving it to children.  

6. Consider Tying Probiotics

A healthcare provider may advise taking probiotics to treat the stomach flu. Probiotics are live microbes in your gut and certain foods. Some probiotic supplements help ease stomach flu-related symptoms like diarrhea.

Some evidence suggests that probiotic supplements help shorten the duration of diarrhea. Probiotics that may help treat the stomach flu include Bifidobacterium infantis and Lactobacillus rhamnosus.

Note that the Food and Drug Administration does not evaluate the efficacy of supplements before they are on the market. Talk to a healthcare provider before starting a new supplement. 

Most cases of the stomach flu resolve on their own within a few days. In contrast, you or someone you are caring for may require medical attention for dehydration or severe symptoms.

Consult a healthcare provider right away if you have:

• Black, tar-like stool that contains blood or pus
• Changes in your mental state
• Diarrhea that lasts two days or longer
• High fever
• Severe abdominal or rectal pain
• Signs of dehydration (e.g., fainting, feeling dizzy, and rapid heart rate)

Older adults, pregnant people, and those with weak immune systems may see a healthcare provider if they develop stomach flu symptoms to prevent severe illness.

Seek immediate medical attention if an infant or young child with the stomach flu develops signs of dehydration, such as becoming irritable, crying without tears, and having no wet diapers for three hours or longer.

You can help reduce stomach flu symptoms at home by replenishing fluids and electrolytes, getting plenty of rest, and taking medications like Imodium or Pepto-Bismol. Staying as hydrated as you can is essential to prevent dehydration.

Most people recover from the stomach flu within a few days, but some may develop severe symptoms. Contact a healthcare provider if you have a high fever, develop severe diarrhea and vomiting, or show signs of dehydration. Avoid making or sharing food with others for at least two days after your symptoms resolve to avoid spreading the stomach flu.