Linalool is a floral-scented terpene that is found in a variety of plants, including lavender, basil, and coriander. This terpene has demonstrated sedative effects in animal studies and is thought to be helpful in treating anxiety disorders and chronic pain. (side note: Linalool is also an effective insecticide and has been shown to be particularly lethal to cockroaches.)

It sounds like the effects of Linalool are currently being studies in humans, but some promising research has already started on mice.

Here's an article published in Phytomedicine, an International Journal of Phytotherapy and Phytopharmacology: "Effects of inhaled Linalool in anxiety, social interaction and aggressive behavior in mice" published back in July of 2010.