The exculpatory statement that a positive THC finding in the blood is due to the consumption of hemp products or passive exposure to cannabis smoke has been disproved by the monitoring of hemp products and recent passive inhalation studies conducted in social settings, which showed that these conditions are unlikely to produce a positive result in the blood. The defense that the ingestion of Indian olibanum may result in a positive THC concentration in the blood is unusual; it is based on older publications where authors had speculated on a possible association of the synthetic pathways of THC from terpenoid precursors also being present in olibanum and the biogenesis of THC in hemp. It had further been speculated whether chemical or plant-derived pathways may also occur in humans. A thorough understanding of the different pathways and recently published results have outdated these speculations.