These results, which are yet to be peer-reviewed, stem from a 12-week study where it's been found that mouthwashes containing at least 0.07 percent cetypyridinium chloride (CPC) show "promising signs" of killing off the virus. 

In the laboratory tests, scientists at the university worked with various mouthwash brands, including Listerine and Dentyl. By mimicking the conditions of a person's naso/oropharynx passage, they tested how various mouthwash ingredients are at killing the virus. 

In their report, titled The Virucidal Efficacy of Oral Rinse Components Against SARS-CoV-2 In Vitro, researchers note that three of the mouthwashes tested eradicated the virus completely in the lab.

These early results from Cardiff are not the same as finding a cure: There is no indication that mouthwash has any impact on the virus if it moves from human saliva into lung tissue, for example.