Four major findings are reported. First, chemometric analysis of mass spectrometry-derived chemical fingerprints of plants of abuse can be used to identify and differentiate one from another. Second, a reliable set of experimental parameters were developed that could be used to reproducibly generate species-specific mass spectral fingerprints that can be used to identify legal high plants of abuse. Third, validated protocols were developed that enabled quantification of the psychoactive components of plant-based legal highs. Fourth, a highly robust and accurate database, along with an accompanying statistical analysis processing workflow was developed, against which the spectra of plant-based legal high unknowns can be screened, and which enables their species-level identification, with reporting of the statistical accuracy. The hypothesis was investigated through four tasks, which this report describes. This is followed by a description of data analysis. In discussing the implications of the project findings for criminal justice policy and practice in the United States, this report states that the project resulted in the development of needed innovations that had been lacking in the forensic analysis of mind-altering plants. Publications and conferences in which project findings and implications are discussed are listed.