'febrific' originates from Latin, specifically the word 'febris' and the Late Latin adjective 'febrificus', where 'febris' meant 'fever' and the element '-ficus' (from 'facere') meant 'making' or 'producing'.

'febrific' changed from the Late Latin/Medieval Latin word 'febrificus' and was borrowed into English in the 17th–18th centuries as 'febrific'.

Initially, it meant 'making or producing fever', and over time it has retained that basic meaning but has become rare and chiefly literary or scientific in usage.