'bacteriotherapeutic' originates from Modern English, specifically the combination of the prefix 'bacterio-' (from New Latin 'bacterium') and the adjective 'therapeutic' (from Greek via Latin/Old French), where 'bacterium' traced to Greek 'bakterion' meant 'small staff' and 'therapeutic' traced to Greek 'therapeuein' meant 'to attend, treat'.

'bacteriotherapeutic' developed by combining the 19th–20th century scientific prefix 'bacterio-' (from New Latin 'bacterium', itself from Greek 'bakterion') with 'therapeutic' (from Greek 'therapeuein' → Latin/Medieval Latin 'therapeuticus' → Old French → Modern English), producing a modern technical adjective.

Initially the elements referred separately to 'bacteria' and 'treatment'; over time the compound has come to specifically denote methods or agents that use bacteria for therapeutic purposes ('treatment using bacteria').