'antianaphylactogen' originates from a modern compound of Greek-derived prefix 'anti-' (from Greek 'anti' meaning 'against') and the Neo-Latin/medical formation 'anaphylactogen' (itself built from 'anaphylaxis' + suffix '-gen', where '-gen' meant 'producing' or 'originating').

'antianaphylactogen' formed in modern medical English by adding the prefix 'anti-' to 'anaphylactogen'. 'Anaphylactogen' derived from the early 20th-century coinage 'anaphylaxis' (from Greek elements such as 'ana-' and 'phylaxis') combined with the suffix '-gen' to denote an agent related to producing or eliciting a response.

Initially coined to denote 'an agent that prevents or counteracts anaphylaxis'; the term has remained narrowly medical, referring specifically to substances used to inhibit or prevent anaphylactic reactions.