Abracadabra

Abracadabra: what was it used for?

Written on parchment and hung at the neck against fever, which was meant to shrink as the word did.

Abracadabra: what did the older authorities say?

Serenus Sammonicus

Prescribes the word written in a narrowing triangle and hung from the neck with linen thread against the fever.

Serenus Sammonicus

Gives the word in his Liber medicinalis against the hemitritaeos, the semi-tertian fever, which he calls “more deadly” and says no Roman ever named in his own tongue: written on a sheet, repeated beneath with a letter taken away each time until it narrows to a cone, and bound about the neck with linen.

Daniel Defoe

In A Journal of the Plague Year (1722) lists the word among the charms the people of London wore in 1665, “as if the plague was not the hand of God, but a kind of possession of an evil spirit,” and holds that the wearers died with the rest.

The Catholic Encyclopedia

The Catholic Encyclopedia notes that in Egyptian magic “a mere agglomeration of vowels or of meaningless syllables was supposed to work good or evil. Their barbarous sounds were the object of ridicule to the man of common sense. In many cases they were of Jewish, or Babylonian, or Aramaic origin and because unintelligible to Egyptians, the words were generally corrupted beyond recognition.” It cites Pliny as “the earliest writer who mentions amulets,” and St. Cæsarius of Arles, from whose sermons “it appears that the dispensing of amulets was a regular profession; each disease had its appropriate amulet.”