Metal bottle of "Pepsodent" tooth powder, by Pepsodent Ltd., London

Pepsodent tooth paste contained ‘irium’, described as a ‘magic’ ingredient that would whiten yellow teeth. This popular product used the then famous advertising slogan “You'll wonder where the yellow went when you brush your teeth with Pepsodent!” In reality, irium was simply a chemical compound of sodium.

Pepsodent Co. Inc. was an American company based in Chicago which opened up branches in other parts of the world, including London. Although the Pepsodent company was bought by Unilever in 1944, the brand is still available today.