The method includes the steps of performing in-vitro liver, intestinal and/or expressed enzyme assays with selected ethnobotanical substances, for both humans and a variety of animal species, to produce an array of resulting chemical entities, such as metabolites, for the human and the animals. Comparisons are then made between the chemical entities from the human in-vitro studies and the animal in-vitro studies to determine the closest match. The animal with the closest match is then used for an in-vivo study. If a match is present between the animal in-vivo results and the human in-vitro results, the matched chemical entity is isolated or synthesized and then further tested to determine the suitability of the matched chemical entity as a treatment drug.