Phylaxis, a word seldom used, stands in the Greek for protection. Anaphylaxis will thus stand for the opposite. Anaphylaxis, from its Greek etymological source, therefore means that state of an organism in which it is rendered hypersensitive, instead of being protected.

Nobel Lectures, Physiology or Medicine 1901-1921 - Nobel lecture for award received in 1913 - Anaphylaxis (p. 473), Elsevier Publishing Company. Amsterdam, Netherlands. 1967