The smell of rosemary essential oil may help enhance prospective memory- the ability to remember upcoming events in order to complete future tasks, like sticking to a medication schedule or sending an email.

Rosemary has been medicinally linked to memory since ancient times, when the ancient Egyptians used it in fidelity rituals at weddings and funerals. The Telegraph pointed out that Shakespeare made what might be the most famous literary reference to the herb in Hamlet, when Ophelia announced "There's rosemary, that's for remembrance: pray, love, remember."

Psychology researchers from Northumbria University presented their findings about the herb's health benefits for healthy adults at the British Psychological Society's annual conference this morning, suggesting that rosemary aromatherapy may have potential in treating people with memory impairments that hamper everyday functioning.

"We wanted to build on our previous research that indicated rosemary aroma improved long-term memory and mental arithmetic," said lead researcher Dr. Mark Moss in a statement.

His previous studies found that rosemary essential oil contains an organic chemical compound called 1,8-cineole (also known as eucalyptol) that boosts the chemical brain systems behind cognitive performance when absorbed into the bloodstream of healthy adults.

Moss recruited 66 participants to complete a series of prospective memory tests while assigned to either an unscented room or one scented with rosemary essential oil. They also filled out mood questionnaires and provided blood samples so researchers could assess the concentrations of 1,8-cineole in their system.

The tests included prospective memory tasks like hiding objects and then finding them later, and passing a specific object to the researcher at a particular time. All the tasks had to be done without prompts, and if the participant forgot to perform any of them, they would be given prompts that lowered their score.

The results showed that smelling rosemary oil did indeed boost participants' performance on the prospective memory tasks, and that higher scores correlated to much greater concentrations of 1,8-cineole circulating in participants' blood.

There was no connection between participants' mood and their memory scores, suggesting that their superior performance was tied to the pharmacological influence of 1,8-cineole, not just a result of heightened alertness from smelling a pleasant aroma.

1,8-cineole is a terpene, a small fat-soluble organic molecule that can easily enter the bloodstream through mucosal linings in the nose or lungs, then cross the blood-brain barrier. 1,8-cineole is found in many aromatic plants aside from rosemary, including eucalyptus, bay, wormwood and sage, and usually makes up 35 to 45 percent of rosemary essential oil.

Other studies have found that 1,8-cineole inhibits the enzyme that breaks down acetylcholine (ACh), an important neurotransmitter in the nervous system that is related to memory and cognition. It may also have anti-inflammatory and pain relief properties, which explains rosemary's common usage today as an herbal medicine.

 "Remembering when and where to go and for what reasons underpins everything we do, and we all suffer minor failings that can be frustrating and sometimes dangerous," said research coordinator Jemma McCready, in the researchers' statement.

She and Moss hope to conduct further research on rosemary oil's health benefits for adults with age-related memory decline, or other groups with memory deficits.