Pete Farmer says: "On a recent trip to the Mid-East, I noticed that I was strangely attracted to a particular type of incense, which seemed to be quite common. A Syrian companion told me it was called 'oud', and explained that it was formed by a fungus which attacks the agarwood tree. Although this was new information for me, it has been known throughout antiquity. He took me to a specialty shop, where I purchased a very small amount of this rare and precious material.
"On my return, I declared the stuff at Swiss customs, and after a brief delay, they told me it was okay. Research on the 'Net lead me to U. of M.'s interesting site. It has had a similarly compelling attraction on my whole family, and has become somewhat of an addiction. Beware: if you're the type of person who succumbs easily to substance abuse, once you try this stuff there may be no going back! Weird." Link