Most (but not all) people who eat asparagus subsequently void urine that has a strange funky odor. Chemists have addressed this phenomenon, of course, and have proposed the compounds shown in the accompanying photo. Some researchers have suggested that methylmercaptan and the sulfides and disulfides on the top line are responsible for the odor. However, we (and by that I mean I) know better. Those compounds probably contribute to the aroma but are clearly not the whole story to a chemist having experience with sulfur compounds. The main component of the urine odor is due to the 2 thioesters (structures I and II) shown in the center. They probably arise from the metabolism of methylmethionine (anion not shown) and asparagusic acid seen on the bottom line.
