What mouthwash used the phrase a handshake instead of kiss?

The mouthwash that used the phrase "a handshake instead of a kiss" in its advertising campaign was Listerine.

This tagline was used in the 1980s and 1990s and aimed to emphasize the importance of fresh breath in social interactions. It played on the idea that bad breath could be a social barrier, and Listerine offered a solution.