There are approximately 12 species in the genus Datura, a member of the nightshade family known for its toxic chemical content. This herbaceous plant can reach up to two meters in height and has large, trumpet-shaped flowers. Datura is an opportunistic genus that tolerates arid climates and can be invasive outside its native range. Our research is concerned with two toxic compounds, atropine and scopolamine, that are present in all Datura species and are believed to have evolved as a response to herbivore attack. Atropine and scopolamine are thought to exist in erratic levels, making it difficult to predict chemical concentrations. In addition to being powerful predator deterrents, these compounds can cause severe poisoning and death in humans. Conversely, both chemicals are commonly used in pharmaceuticals to treat conditions such as gastrointestinal spasms and colic. Datura also has a long history of use in various cultures as a sacred entheogen. To understand the chemical variation in Datura, we conducted a comprehensive meta-analysis. Through the Web of Science database, we recovered 89 peer reviewed papers using the search terms "Datura atropine scopolamine" and extracted chemical concentration data from 18 of these. We also added additional papers from a citation search. We then looked at the variation of these compounds within species of Datura and throughout the genus. Our intention is to provide evidence that the variability of scopolamine and atropine concentrations in Datura are a result of genetics, and that this trait has allowed the plant to combat predation. Determining the degree of unpredictability in these compounds will give us important insights into evolutionary processes, invasive species management, and a deeper appreciation of the ethnobotanical uses of this mysterious plant. We hope our study will be the first to supply direct evidence supporting this hypothesis of evolved variability.