Heather N. Kolich, ANR Agent, UGA Extension Forsyth County

As Americans are wont to offer a bowl of chicken soup for relief from colds and flu, Brits are known to offer a cup of tea to counter stress. Research from the University of Georgia now suggests drinking tea may be effective in preventing infection with COVID-19.

A glass tea cup sitting on a cork coaster, with a light green tea brewing inside. A garnish of mint leaves is sitting on the coaster.
Mint teas, specifically mint medley and eucalyptus mint, are among the five varieties of teas that inactivate the COVID-19 virus in saliva. Photo by Laark Boshof on Unsplash.

When the COVID-19 pandemic began, UGA Center for Food Safety virologist Malak Esseili included tea among her efforts to protect her family from the disease. She chose tea because it’s readily available, easy to prepare, and tasty. Plus, it has long been used in several cultures as a treatment for respiratory illnesses.

Then she began laboratory tests to learn how tea affects the SARS-CoV-2 virus. Her research indicates that certain types of tea “inactivate” the virus in saliva. The virus replicates in the mouth. If it’s inactivated in saliva, however, it doesn’t move further into body when we swallow, so there’s less chance active virus will reach the respiratory system.

In laboratory testing, Esseili and Julianna Morris, a graduate student in Food Science and Technology, identified five teas – raspberry zinger, eucalyptus mint, mint medley, green tea, and black tea – that reduced the COVID-19 virus in saliva by 96-99.9% within 10 seconds when prepared as drinkable hot tea. The researchers steeped one tea bag per cup of hot water for 10 minutes. The brew was tested without milk, sugar, or other additions. Black tea proved to be the most effective.

A concentrated gargle prepared with each of the tea varieties was also 99.9% effective at inactivating the SARS-CoV-2 virus. The researchers prepared the gargle at four times the strength of the beverage.

Results indicate that regularly drinking certain varieties of hot tea can have a preventive effect against infection by COVID-19. The researchers suggest that drinking or gargling tea shortly after exposure to the virus could provide “a rapid at-home intervention . . . to reduce infectious SARS-CoV-2 load” in the mouth and saliva.

“At this stage, we are not suggesting tea as a stand-alone intervention against SARS-CoV-2,” Esseili said in an interview with UGA College of Agricultural and Environmental Sciences Newswire writer Jennifer L. Reynolds, “because the virus also replicates in the nose and may have already reached the lung by the time a person tests positive.”

Clinical trials are needed to understand what effect tea drinking could have for a patient who is ill with COVID-19. While Esseili stresses that tea is not a substitute for medical care, she said that a cup of tea “can be an additional layer of intervention that patients and their families can easily adopt on a routine basis.”

In other words, enjoy a daily cup of tea. It can’t hurt, and it could keep you healthy.

Morris and Esseili’s findings are published in the journal Food and Environmental Virology at https://link.springer.com/article/10.1007/s12560-023-09581-0.  

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