In a study reported in the British Medical Journal Lancet, elderly patients(with sleeping problems) slept "like babies" when a lavender aroma was wafted into their bedrooms at night. Studies with brain wave frequency has shown that smelling lavender increases alpha waves in the back of the head, which are associated with relaxation.
In another study , the keyboard typing errors dropped 33 percent, when exposed to jasmine (an uplifting fragrance).....Fragrance of Jasmine increases beta waves in the front of the head, which are associated with a more alert state.
However,when exposed to lemon fragrance (a sharp, refreshing stimulant), the mistakes fell by a whopping 54 percent!