Kolynos was the name of an old-time line of oral care products that was created by N.S. Jenkins in 1908 and acquired by Colgate-Palmolive in 1995.
Although not now readily available in the US, the brand remains strong in Latin America, and also manufactured in Hungary. In Brazil, for instance, Kolynos was the second best-selling brand, after Colgate itself. Because of antitrust concerns at the time of the acquisition, Colgate-Palmolive agreed to suspend marketing Kolynos-branded toothpaste in Brazil for a number of years. However, Colgate-Palmolive shortly began selling what was essentially the same product, with very similar packaging and marketing, under a new brand called Sorriso ("Smile" in Portuguese), successfully transferring most of the customer loyalty to the new brand. Kolynos jingles have been written in several languages. In Peru, Kolynos is synonymous with toothpaste and a big smile can be called a Kolynos smile.
Everybody was asleep or out or home for the week end, and it was very, very quiet and depressing in the corridor. There was this empty box of Kolynos toothpaste outside Leahy and Hoffman's door, and while I walked down towards the stairs, I kept giving it a boot with this sheep-lined slipper I had on.
The brand is also mentioned in The Black Gang by Herman Cyril McNeile:
By the way, my boy, you skimped your teeth pretty badly to-night. You'll have to do better to-morrow. Most of your molars must be sitting up and begging for Kolynos if that's your normal effort.