In 1969, the lighting designer Chip Monck, who’d worked the Newport Folk Festival at which Bob Dylan went electric, was conscripted from his tasks onstage at Woodstock to serve as an impromptu master of ceremonies. Monck thereby entered counterculture lore as the man who warned the celebrants against an illicit temptation: “The brown acid that is circulating around us is not specifically too good.”

Whatever may have been not specifically too good in the concoction (and the power of suggestion can’t have helped its users any), in retrospect “brown acid” doesn’t sound very appealing. It is typical, though, of the earthy, dank, subterranean aura surrounding both the actual and the fictional drugs that haunted the late-20th-century imagination, most of which seem to have been composed of weeds, seeds, soil and excreta. With the “Odyssey”’s lotus flowers and nepenthe (possibly opium), and, perhaps, “Alice in Wonderland”’s cake and mushroom in the deep background, novelists in the 1960s and ’70s gave us organic intoxicants like “melange,” the utopian “spice” in Frank Herbert’s “Dune”; “black meat,” a cheeselike drug made from the flesh of giant centipedes in William S. Burroughs’s “Naked Lunch”; and the nightmarishly addictive Substance D (for death) in Philip K. Dick’s “A Scanner Darkly,” an injectable derived from a blue flower grown, in one of Dick’s fiercest ironies, on farms staffed by zombied-out recovering addicts.

The trend’s satirical apotheosis was perhaps attained by Terry Southern in his story “The Blood of a Wig,” from “Red-Dirt Marijuana and Other Tastes.” Southern’s fictional narcotic, called red-split, consists of 90 CCs’ worth of the blood of a schizophrenic, smuggled fresh out of the wards of Bellevue: “Sense-derangementwise, it was unlike acid in that it was not a question of the ‘Essential-I’ having new insights, but of becoming a different person entirely.”

The current generation of fictional drugs, rather than bubbling up from nature’s underworld, parachute into stories and novels from the corporate-technological top down. The recent nightmare drugs — for they are, exclusively, nightmares — are pharmaceuticals. Likely it was Don DeLillo who initiated this great pivot in “White Noise” (1985), with Dylar, an experimental capsule advertised as a cure for the fear of death. A veritable fictional pharmacopoeia followed, from David Foster Wallace (DMZ), George Saunders (Verbaluce) and Jonathan Franzen (Mexican A). In these writers’ hands, the self’s integrity is under assault not by illicit indulgences but by capitalism’s imperative to market us shiny neurological upgrades — and by our complicit desire to be thus reworked.