'Abracadabra' Started Out as a Medical Prescription

The first known prescription of "abracadabra" appears not in a manual of magic but in one of medicine. In the third century, Serenus Sammonicus, a Roman physician and scholar, recommended in his Liber Medicinalis a treatment for persistent fevers (probably malaria): write ABRACADABRA on papyrus and repeat the word line after line with one letter fewer each time, until only a single A remained. The text formed an inverted triangle that the patient wore hanging from the neck.

The logic was that of sympathetic magic: just as the word shrank until it vanished, the illness was supposed to dwindle with it. The origin of the term is still debated — Aramaic and Hebrew roots have been proposed — but its career as a talisman is documented for centuries: as late as the Great Plague of London in 1665, some residents nailed the triangle to their doors.

Only much later did the word leap from the medicine chest to the stage. When a magician says it today before a trick, they are unknowingly prescribing one of the oldest remedies on record. Effectiveness not guaranteed.