According to Google Trends, interest in the search term “Kratom” has increased sharply from 2011—by a factor of three. Insider blogs note that it trends higher than many other supplements. What’s more, vastly conflicting descriptions of its benefits and side effects are all over the Web, along with troubling reports of adulterated versions of the substance being sold online. Not surprisingly, eager beaver regulators have jumped into the fray. But what, exactly, is Kratom? Formally known as Mitragyna speciosa, it is a tree that grows from 3-20 meters (10-66 ft) tall, native to Southeast Asia. The plant is a member...