Many years ago, European traders used to exchange 1 pound of patchouli, for a pound of gold (1 pound of gold was worth 1 pound of patchouli).
Patchouli oil is shown to decrease sympathetic nervous activity, which is responsible for the fight-or-flight response in the body. This, in conjunction with its shown ability to reduce heart rate makes it stress-relieving. The oil is also recorded to be both a stimulant, which supports its historic use as an aphrodisiac, and a relaxant through its ability to increase Alpha brain waves. This simultaneous stimulating and relaxing activity is perhaps why it is also used prior to meditation and considered to be a “euphoric” and anti-depressant.