Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 148,110 pages of information and 233,634 images on early companies, their products and the people who designed and built them.
The Pepsodent Company of 40 Holborn Viaduct, London, EC1 (1922).
Pepsodent is a brand of toothpaste with a wintergreen flavour. It was formerly owned by Unilever. (but, since 2003, by Church and Dwight in USA).
It was advertised for its purported properties fighting tooth decay, attributed in advertisements to the supposed ingredient Irium. Irium is another word for sodium lauryl sulfate, an inexpensive ionic surfactant.
Its best-known slogan was “You'll wonder where the yellow went / when you brush your teeth with Pepsodent!”