Claims have long circulated about lavender's ability to prevent balding, control mild burns and acne, as well as treat gastrointestinal disorders. But lavender's impact on mood and cognition has garnered the most attention. A study by researchers at Charles Sturt University in Australia reviewed trials testing the outcomes of lavender aromatherapy. It seems there is mounting evidence that the essential oil does have physiological effects.

To measure the effects of aromatherapy, researchers compared responses with two essential oils thought to have opposite effects on alertness: soothing lavender and invigorating rosemary. One University of Miami study followed brain activity with an EEG machine, finding that the group subjected to lavender aromatherapy did in fact show brainwaves suggesting drowsiness, while the group subjected to rosemary experienced increased alertness.

What's more, everyone in the study reported a mood boost in response to the pleasant scents: The lavender group felt less depressed and the rosemary group had lower levels of anxiety than before aromatherapy. A similar study from the University of Northumbria in the United Kingdom replicated these mood results: the rosemary-treated group was more alert than the group exposed to lavender. But both groups were on the same side when it came to disposition: the lavender and rosemary groups reported significantly better moods than the subjects who weren't given any olfactory supplements.

When it comes to lavender's soothing claims, science seems to be giving the nod to aromatherapy's validity. If that doesn't make you sleep better tonight, maybe a sprig of lavender under your pillow will do the trick.