In the last year alone, kratom has made special guest appearances in several hysterical local news reports, which attracted unwanted attention from the FDA and stirred efforts by several states to ban it outright. Yet the drug, whose effects on humans have never been studied seriously, hasn't had quite the same galvanizing effect on the popular imagination as other fringe substances.

Oft-billed as a benign natural herb from Southeast Asia, kratom lacks krokodil's flesh-eating properties and salvia's storied freakout sessions. It hasn't killed teens or sent hundreds to the hospital, like Spice, K2 and other strains of synthetic marijuana. Nor is it known for inducing the kind of psychotic zombie episodes brought to you by bath salts.Kratom is derived from the leaves of the Mitragyna speciosa tree, which are harvested and dried for use as tea, or ground down further into powder. 

Yet its popularity continues to spread, mostly undetected, across the far reaches of the Internet. Dozens of online vendors now peddle strains to head shops or directly to consumers, who chew, brew, snort, smoke, ingest and even inject kratom. In fact, kratom is now more widely searched on Google than salvia, krokodil, bath salts or synthetic marijuana. And unlike those flashes in the pan, which receded as rapidly as they spiked, interest in kratom has climbed steadily over a decade.