Green tea, a staple of Japanese culture now enjoyed in many American homes, contains compounds called catechins that have significant antiviral activity against influenza, report researchers from Thailand’s University of Phayao in the journal Molecules. They analyzed eight studies involving 5,048 people and found that gargling or drinking green tea reduced the risk of influenza by 33 percent in randomized controlled trials and by 48 percent in longitudinal cohort studies.