Unlike those for our other senses, the neurologic pathways involved in the sense of smell go straight into the memory centers of the brain. This has led researchers to investigate using pleasant smells to improve memory.

A recent article on Medscape described a small study where participants inhaled aromas from essential oils while they slept each night for six months.

Compared to a control group, those inhaling the scented materials had a substantial improvement in memory.

The original scientific publication in Frontiers in Neuroscience describes how the participants were instructed to use the essential oils:

Individuals assigned to the olfactory enrichment group were provided with an odorant diffuser (Diffuser World) and 7 essential oil odorants (rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender; from The Essential Oil Company (link below), Portland, OR) in identical glass vials that each fit into the diffuser. They were asked to turn on the diffuser when they went to bed, and the odorant was released into the air during the night for 2 h when they first went to sleep. They rotated through the different odorants each night.

The participants described the odors as pleasant; I dislike the smell of lavender, so if I decide to try this, I will leave it out of the rotation.

Both the original article and the discussion on Medscape said that the study was small and needed to be repeated with larger groups of participants. Having said that, I see no risk in trying this; if you do and find it helpful, please let me know!