Rosemary is one of many traditional medicinal plants that yield essential oils.
The Brain, Performance and Nutrition Research Centre at Northumbria University, UK designed an experiment to investigate the pharmacology of one of rosemary's main chemical components.
The investigators tested cognitive performance and mood in 20 subjects, who were exposed to varying levels of the rosemary aroma. Using blood samples to detect the amount of 1,8-cineole participants had absorbed, the researchers applied speed and accuracy tests, and mood assessments, to judge the rosemary oil's affects.
Results indicated that concentration of 1,8-cineole in the blood is related to an individual's cognitive performance, with higher concentrations resulting in improved performance. Both speed and accuracy were improved. The oil did not appear to improve attention or alertness.
The same 1,8-cineole is also found in aromatic plants, such as eucalyptus, bay, wormwood, and sage.