Are humans unwitting partners in evolution with psychedelic plants? Darwin's Pharmacy shows they are by weaving the evolutionary theory of sexual selection and the study of rhetoric together with the science and literature of psychedelic drugs. Long suppressed as components of the human tool kit, psychedelic plants can be usefully modeled as "eloquence adjuncts" that intensify a crucial component of sexual selection in humans: discourse.

Psychedelic plants seduce us to interact with them, building an ongoing interdependence: rhetoric as evolutionary mechanism. In doing so, they engage our awareness of the noosphere, or thinking stratum of the earth. The realization that the human organism is part of an interconnected ecosystem is an apprehension of immanence that could ultimately benefit the planet and its inhabitants.

To explore the rhetoric of the psychedelic experience and its significance to evolution, Doyle takes his readers on an epic journey through the writings of William Burroughs and Kary Mullis, the work of ethnobotanists and anthropologists, and anonymous trip reports. The results offer surprising insights into evolutionary theory, the war on drugs, the internet, and the nature of human consciousness itself.