One Anglo-Saxon treatise recommends rubbing hare brains on the gums of a teething baby. Later medieval remedies include rubbing honey mixed with some salt on its gums or letting the baby chew on licorice root. Cloths dipped in milk could also be used both as a kind of baby-bottle and for them to teethe. Later medieval sources (Italian) suggest that babies could be given smoothly polished piece of red coral to teethe on. (A peasant woman wouldn't be able to afford this one.) Burchard of Worms’ Corrector et Medicus from the early 11th-century source recounts this bit of last-resort superstition: “I speak of those who have bawling babies. [The mothers] dig a hole in the ground and make a tunnel through to the other side; then they pull their baby through the hole and say that this stops the baby’s crying. If you have done or approved of such, you should do five days of penance on bread and water.”

Source: Nicholas Orme, Medieval Childhood (2001) and Paul Newman’s Growing up in the Middle Ages (2007).