A swish of mouthwash isn’t a cure of COVID, but there are few downsides. “Mouthwash doesn’t replace other measures we’re currently practicing, like the mask, hand washing, and social distancing,” said. Dr. Kami Hoss, co-founder and CEO of The Super Dentists. “But mouthwash could serve as an extra layer of protection for people who may be asymptomatic and plan to be around loved ones for the holidays.”