Operation Vape Trail' cracks down on synthetic marijuana, 7 OH, kratom, more Today, we announced the issuance of seven warning letters to companies illegally marketing products containing 7 hydroxymitragynine (7 OH). https: www.fda.gov news events press announcements fda issues warning letters firms marketing products What Is 7 Hydroxymitragynine & Why Is It Dangerous? Mountainside TC 7 OH Vape 7 Oh Hydroxymitragynine Vape 7 Oh Vape Kaufen Parents: Have You Heard of 7 OH? A new substance called 7 OH ( 7 Hydroxymitragynine) is starting to appear in gas stations, vape shops, and online stores, and many people don't realize the risks. FDA and Kratom FDA