Methods. References to drug plants among the Classical writers, and archaeological evidence are examined to support this hypothesis. Among the latter, we note the retrieval of macrofossil remains of psychoactive plants, the presence of drug alkaloids in utensils and metabolites in skeletal remains, and artistic depictions of plant species with these properties. Results. Diverse psychoactive plants (Ephedra spp, opium poppy, hemp, ergot, some members of the Solanaceae) have been recovered in prehistoric sites of Europe. This does not imply, however, the exploitation of the psychoactive properties of these species in all cases. Conclusions. Drug-taking is a long-established habit whose origin can be traced back to Prehistory. In those times, drugs were consumed both in ritual ceremonies and medical treatments.