'epitheliotoxic' is a modern English formation combining the New Latin/Greek-derived prefix 'epithelio-' (from 'epithelium') and the combining form '-toxic' (from Greek/Latin roots meaning 'poisonous').

'epithelium' comes from New Latin, from Greek elements 'epi-' meaning 'upon' and 'thēlē' meaning 'nipple' (originally describing a covering tissue), while '-toxic' derives from Greek 'toxikon' (poison, from 'toxon' meaning 'bow', later 'poison used on arrows') via Latin 'toxicus'; these elements were combined in modern scientific English to form 'epitheliotoxic'.

The compounded term initially and consistently means 'poisonous or harmful to epithelial tissue'; its meaning is essentially literal and technical rather than metaphorical, so it has not undergone major semantic shift.