A Facebook post claims drinking grape juice can prevent the stomach flu.

Verdict: False

There is no evidence that drinking grape juice can prevent the stomach flu. The claim has been disputed by experts.

Fact Check:

The stomach flu, also known as “viral gastroenteritis,” is an intestinal infection contracted through contact with an infected person or by ingesting contaminated food or water, according to the Mayo Clinic. Its symptoms can include “watery diarrhea, pain or cramping in your abdomen, nausea or vomiting, and sometimes fever,” the National Institute of Diabetes and Digestive and Kidney Diseases reported.

A post shared on Facebook claims the infection can be prevented through a simple trick: drinking grape juice. The post includes an image of a bottle of Welch’s 100% Grape Juice along with text that reads, “Avoid Stomach Flu With This Trick!” The post’s caption goes on to explain the alleged trick. “Drink a glass of grape juice 3 times a day after being exposed,” reads the caption. “The grape juice changes the pH in your intestinal tract so the virus can’t multiply.”

The pH scale ranges from 1 to 14, according to the United States Geological Survey, and is used to measure the acidity or basicity of a solution, according to Merriam-Webster. (RELATED: Did The 2009 Swine Flu Pandemic Kill 18,000 Americans?)

There is, however, no evidence that grape juice can prevent the stomach flu, according to medical experts. Dr. Gerald Evans, a professor of medicine, biomedical & molecular sciences and pathology & molecular medicine at Queen’s University, told Check Your Fact in an email that the claim “is not based on any science I am aware of.”

“The ability of gastrointestinal viruses like Norovirus to infect a host are unaffected by pH levels in the gut nor by any components in grape juice such as Vitamin C or electrolyte composition,” said Evans. He also noted that “Grape juice does not significantly alter gut pH that would impact on viral replication or infectiousness.”

Dr. John Lednicky, a research professor of environmental and global health at the University of Florida, agreed with Evans that the claim had no basis in fact.

“Our stomachs have acid (gastric acids) that are quite strong (pH as low as 1), yet gastrointestinal viruses survive that strong acid to cause infections,” said Lednicky in an email to Check Your Fact. “Grape juice is mildly acidic, in comparison to the strongly acidic stomach acids. So if anything, drinking too much grape juice might actually raise the acidity of the stomach. Bottom line: The answer to your question is no….the concept is a myth that has been perpetrated on social media but has no validity.”

Versions of the Facebook claim have also been debunked in articles from Men’s Health and Healthline.

Viral gastroenteritis frequently lacks a specific medical treatment, according to the Mayo Clinic. The medical center recommends rest and a slowly increasing, easily-digestible bland diet as the best way to treat the infection.