Reconstructing plant use before domestication is challenging due to a lack of evidence. Yet, on the small number of sites with assemblages, the wide range of different plant species cannot be explained simply in terms of nutrition. Assemblages from the Lower Paleolithic to the Early Neolithic were examined to investigate the relative edible and medicinal properties of the plants. The assemblages contain a mixture of edible species, plants that are both edible and medicinal, and plants with only medicinal properties. The proportion of medicinal plants at all sites is well above the natural average and increases over time. Mechanisms for preventing intestinal parasitic infections are common among animals and together with chimpanzees' preventative and curative self-medication practices suggest an evolutionary context for this behavior. A broad-spectrum approach to plant collection is likely to have been in place throughout the Paleolithic driven, in part, by the need for medicinal compounds.