The Oldest Known Toothpaste Recipe
The oldest surviving recipe for toothpaste is inscribed in black ink on papyrus, and comes from the fourth or fifth century AD. People who have tried the toothpaste say that it's prone to making the gums bleed, but also that it's quite advanced for its time. The recipe specifically calls for one drachma of rock salt, two drachmas of mint, one drachma of dried iris flower, and 20 grains of pepper to be ground and mixed.
from National Geographic
Key Facts In This Video
The average U.K. citizen will go through 80 liters of toothpaste in their lifetime. (0:03)
During World War II, German scientists developed radioactive toothpaste made with thorium. (0:49)
Learn how to make toothpaste at home: (2:01)