The meaning and significance of the name Myddfai is not clear and no satisfying explanation has yet been offered. As David B James, in his book ‘Myddfai, it's Land and Peoples’ said,
“It is very probable that the word, Myddfai, has some specific meaning and possibly with a physical significance. This is suggested by the fact that the word is not unique to the one locality but is also seen as the name of a hamlet rendered Blaenmyddfai or Mothvey, which is within the parish of Llanarthne.”
During the thirteenth century, so the records say, Myddfai was much frequented by physicians and a collection of medicinal remedies was compiled. A study of these recipes shows that Welsh medicine was far in advance of most of Europe at that time, with directions given as to the quantities and methods of preparation of the ingredients – most unusual at that time. The medicines recommended were to be carefully prepared and administered to treat all kinds of ailments, most of which were related to the living and working conditions prevailing at the time.