The relationship between humans and psychoactive substances can be traced back over millennia. This paper aims to provide a comprehensive overview of the consumption of drug plants and fermented beverages in prehistoric times by drawing upon some archaeological examples world- wide that illustrate the early use of these substances. The archaeological evidence of psychoactive substances is assessed in the light of some indicators that should be taken into consideration when examining this type of data. Keywords: psychoactive substances; prehistory; methodology; contexts; ritual