The word "concoct" entered English in the 1530s, borrowed directly from Latin concoctus, the past participle of concoquere. This Latin verb combines con- (together) with coquere (to cook), and it traces back to the Proto-Indo-European root *pekʷ- (to cook, to ripen). The same PIE root gave rise to "cook" itself (through Germanic *kokaz, borrowed from Vulgar Latin), "cuisine" (through French), and "biscuit" (etymologically "twice-cooked").
The earliest English uses of "concoct" were not culinary but medical. In Galenic medicine, which dominated European medical thought from antiquity through the Renaissance, digestion was understood as a process of "cooking" — the stomach's natural heat supposedly transformed raw food into usable nutrients through a series of stages called concoctions. The first concoction occurred in the stomach, the second in the liver, and the third in the tissues. A physician might say that a patient's stomach had failed to properly "concoct" their
This medical sense persisted well into the 17th century, but the more general meaning of "preparing by mixing ingredients" emerged alongside it. By the late 16th century, writers were using "concoct" for any process of combining disparate elements into a unified product. The figurative extension to mental activity — concocting a plan, a story, or an excuse — followed naturally. The semantic chain runs: cooking
The PIE root *pekʷ- produced an interesting split in its descendants. In Latin, coquere retained the straightforward meaning of cooking. But the related form *pekʷ-os gave Latin praecox (ripening early, precocious), because fruit that ripens ahead of schedule was understood as having been "cooked" prematurely by the sun. This same metaphorical logic — cooking as a process
German kochen (to cook) and Dutch koken descend from the same root, though they arrived through a different route — borrowed from Vulgar Latin cocere rather than inherited through regular Germanic sound changes. This makes them learned loanwords rather than true cognates, a distinction that reflects the profound influence of Roman culinary culture on Germanic-speaking peoples.
Modern "concoct" carries a faint whiff of suspicion that its Latin parent lacked. When we say someone "concocted a story," we usually imply fabrication rather than artful composition. This pejorative colouring likely developed because the act of combining disparate ingredients to produce something new can easily shade into the act of mixing truth with falsehood to produce deception.