Stomach flu, or viral gastroenteritis, is a common condition that affects a person’s intestines. Treatment for viral gastroenteritis typically involves replacing lost fluids and electrolytes to help prevent dehydration.

Many people use the term stomach flu to describe viral gastroenteritis. However, it is important to note that influenza viruses, which cause seasonal flu, do not cause gastroenteritis.

Gastroenteritis refers to inflammation of the stomach and intestines.

Several viruses may cause stomach flu, including rotavirus and norovirus, which is the most common cause. Approximately 19–21 million people in the United States get stomach flu each year.

Antacids are medications that can neutralize stomach acid to help relieve heartburn and indigestion.

This article explores whether Alka-Seltzer and other antacids can help to treat stomach flu. It also discusses stomach flu symptoms, treatment, and when to speak with a doctor.

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Antacids are a group of medications that help neutralize acid in the stomach. A person would typically take them to help relieve symptoms of heartburn and indigestion. Antacids may also help relieve symptoms of:

There is no research to suggest that Alka-Seltzer can help to relieve stomach flu symptoms. The active ingredients in Alka-Seltzer include the antacids anhydrous citric acid and sodium bicarbonate. It also contains aspirin, which helps to relieve pain.

However, medications containing the antacid bismuth subsalicylate, such as Pepto-Bismol, may help to relieve diarrhea due to stomach flu.

A person should speak with a healthcare professional for further advice about managing stomach flu symptoms.

Learn more about antacids and how they work.

Viral gastroenteritis typically causes:

Some people may develop a fever. Anyone who experiences symptoms of dehydration, which is the most common complication of stomach flu, should consider consulting a doctor as soon as possible.

Learn more about stomach flu and its symptoms.

According to the United Kingdom’s National Health Service (NHS), most adults recover from stomach flu within approximately 1 week, but this can depend on the individual and the type of viral infection they are experiencing.

A person with stomach flu can help relieve the symptoms of their condition at home by:

  • replacing lost fluids and electrolytes with:
    • water
    • fruit juice
    • sports drinks
    • broths
    • saltine crackers
    • oral rehydration solutions, which include Pedialyte and Naturalyte
  • taking over-the-counter (OTC) medications, such as bismuth subsalicylate and loperamide, to help relieve diarrhea, and acetaminophen to help with fever, aches, and pains
  • eating small amounts of simple foods such as rice, pasta, and bread
  • getting plenty of rest

Sometimes, a healthcare professional may prescribe medications to help control severe vomiting. They may also recommend a person takes probiotics.

If a person suspects their child has stomach flu, they should contact a doctor straight away.

An adult with stomach flu will not need to contact a doctor, as symptoms typically get better at home within about 1 week. However, it is a good idea to talk with a healthcare professional if symptoms do not improve after a few days or if symptoms include the following:

If a person with stomach flu is pregnant or has an underlying health condition, such as a weakened immune system, kidney disease, or inflammatory bowel disease, they should consider consulting a doctor straight away.

If symptoms persist, a doctor may ask a person for a stool sample to determine if bacteria, parasites, or chemicals are causing the gastroenteritis instead of a virus.

Learn more about gastroenteritis in children.

Stomach flu, or viral gastroenteritis, is a common condition that typically causes symptoms such as diarrhea and vomiting.

Antacids are a group of medications that can neutralize stomach acid. Medications containing bismuth subsalicylate, which is a mild antacid, can help relieve diarrhea due to stomach flu.

There is no research to suggest that other antacids, such as Alka-Seltzer, will help symptoms of stomach flu.

A person with stomach flu will typically recover at home. However, contact a doctor if certain symptoms develop, such as high fever, signs of dehydration, or blood in the stool.