Yes, just smelling rosemary might just make you smarter. Healthy volunteers who took a sniff of 1,8-cineole—one of the main chemical components of rosemary—scored better on a math test than people who didn't. In fact, the higher the participants' blood levels of 1,8-cineole, the better their speed and accuracy on the tests.

Interestingly, the 20 healthy volunteers who participated in the study didn't know that the smell of rosemary had anything to do with the study. They were told the smell was "left over" from the previous research conducted in the Brain, Performance and Nutrition Research Centre at Northumbria University in the UK.

If you want to try out rosemary for more brain power, here are some of the study's takeaways. The cubicles in which the study was conducted were infused with rosemary, so you may want to use an aromatherapy diffuser. The participants smelled the scent for either 4, 6, 8 or 10 minutes before the test; the higher their blood levels, the better they did. One of the researchers commenting on the study noted that 1,8-cineole has the power to inhibit an enzyme that plays a role in the development of Alzheimer's disease.

Not only did the rosemary make some of the participants smarter, it also made them feel more content. The intriguing possibility: "Positive mood can improve performance, whereas aroused mood cannot,” said one of the researchers.

This study was published in February 2012 in the journal Therapeutic Advances in Psychopharmacology.