Heracleum or cow parsnips are high-latitude plants that can produce severe inflammation in humans. They seem like the last thing someone would want to ingest. However:
Puchka (Heracleum dulce) is an insidious plant. Its juice has a sweet taste, but leaves blisters and sores on the skin that ache for months! ... Cossacks distilled wine that produced a strange effect: after two or three glasses a person saw wonderful dreams, but in the morning felt so miserable as if he had committed a crime.
A psychoactive drink is made from the plant in Kamchatka.
While the first quote is about something like an accident, the second one seems to describe an ongoing practice. Which culture(s) used this hogweed preparation, and to what ends? Does it still exist today? Is the poisonous part of the plant avoided, and is the preparation truly psychoactive?
(Asked previously on History.SE, -- somewhat resolved there)