The Smell of Asparagus

Asparagus has been known for centuries to cause what the French scholar Louis Lemery called in 1702 a “filthy and disagreeable Smell in the Urine.” The odor comes from methylmercaptan, which is excreted in the urine of anyone who eats asparagus, but its detection depends on whether a person is genetically able to smell it. Not every creature is offended by the smell, and this fact may have been put to patriotic use in World War II, when the United States was rumored to have included spears of asparagus in spy kits. Agents allegedly were instructed to eat the delicacy and urinate into oceans or rivers and lakes, thereby allowing the mercaptans to attract fish, making them easier to catch.