Medicinal and other properties, including psychotropic properties and dyes, are all based on plant secondary compounds, these are properties that are linked to ecological, adaptive and protective functions. An evolutionary context for the use of plant secondary compounds is suggested by the widespread use of medicinal plants for self-medication among animals. Great apes have been shown to deliberately search out medicinal plants that are not necessarily an everyday part of the diet and prepare for ingestion. Given the very extensive evidence for animal self-medication behaviour it is inconceivable that hominins did not practice this. PP will focus on recovering evidence for medicinal plants, and plants with other properties, whose non-edible properties means that they are sometimes considered as accidentally collected ’weeds’ or low-quality food sources, even though many of these have important medicinal or other properties including psychotropic, dyeing, flavours and aromas.