Abstract Botanicals have been in use for a long time for pest control. A product of species coevolution, these compounds offer many environmental advantages. However, their uses during the 20th century have been rather marginal compared with other biocontrol methods of pests and pathogens. Improvement in our understanding of plant allelochemical mechanisms of activity offer new prospects for using these substances in crop protection. We examine the reasons behind their limited use and the actual crop protection developments involving plant allelochemicals, namely: (i) formulations including biopesticides of plant origin for organic or traditional agricultures, and (ii) improvement of plant resistance to pathogens through identification of genes coding for allelochemicals and stimulation of natural passive and active defenses of the plant. Commercial and regulatory aspects are discussed.