Mmm, pass the cheetos, will ya?

Basically, we have no evidence of anything resembling drug cultures in Europe during the Middle Ages (thus no stereotypical red-eyed stoner, manic cokehead, etc). Medieval people certainly drank alcoholic beverages regularly, but they tended to see alcohol abuse as a personal moral failing, related to gluttony. References to consumption of other substances are vanishingly rare (though that does not necessarily mean it didn't happen, just that apparently no one thought it worth writing down). I can think of one early 15th century account in which the future Henry V of England was given an opium mixture in oral form to treat the pain of an arrow-in-the-face injury.