How to Travel With Medical Marijuana

Even as more states allow medical marijuana, traveling between states with cannabis can leave patients in legal limbo. This fall, Sierra Riddle queued up at security at Los Angeles International Airport with a tincture bottle of THC oil — the psychoactive ingredient in cannabis — in her purse. Ms. Riddle, 31, a nursing assistant from southern Oregon, was traveling with her son Landon, 9, and uses medical marijuana to treat his severe nerve pain from…