Mint

 was both a plant and a shade of green. On Earth the plant was not tolerant to rapid changes in temperature and would die back during cold temperatures. (PROSE: Cat's Cradle: Warehead, The Banquo Legacy) When the Tenth Doctor and Donna Noble visited Earth in 1926, the Doctor said that the air smelled of grass and lemonade with a hint of mint. He said that the mint in the air meant that it was the 1920s. (TV: The Unicorn and the Wasp)

Mint as a food
Many sweets were mint flavoured such as humbugs and Tic-Tacs. (PROSE: Coldheart, Interference - Book One) Sweets made of chocolate with mint in the middle were also popular. These were often consumed with tea or coffee following a meal. (PROSE: Dragons' Wrath, Dry Pilgrimage)

Vithiliskan Savoury Fruit was served with mint sauce at the DMMC base canteen on Dreamstone Moon. (PROSE: Dreamstone Moon)

Mint's other uses
Mint was used in to flavour many forms of toothpaste. (PROSE: Sky Pirates, Beige Planet Mars)

A breath mint was a type of candy primarily consumed to freshen the smell of one's breath. (TV: The Eclipse of the Korven)