Allelopathy arises from the release of chemicals by one plant species which affect other species in its vicinity, usually to their detriment. Such natural compounds are called allelochemicals. As awareness grows of environmental pollution involving the use of synthetic chemicals and demand increases for sustainability in agriculture and quality food production for humans, attention is being focused on reducing reliance on synthetic chemicals and finding ways to replace them. Allelopathy holds great prospect for meeting such demands.

Contemporary research in allelopathy focuses on isolating, identifying and quantifying specific active allelochemicals. Once these substances are identified and characterised, they can be used either as natural herbicides or as models for developing new and environmentally-friendly herbicides. Rapid development in analytical technology has made advanced instrumentation (ie. GC-MS) accessible for general disciplines such as agriculture and allelopathy. This has significantly facilitated tasks of allelochemical identification, rapidly increased understanding of allelopathy, and accelerated its application in agricultural practice.

In a case of allelopathic research on silvergrass, a significant weed in southern Australia, GC-MS has been employed to characterise the natural toxins. Twenty-one allelochemicals were identified and quantified. Subsequently, their biological activities were tested and identified through a bioassay procedure, which revealed strong correlations between individual phytotoxins and levels of measured phytotoxicity.