Seems that some U.S. police officers are on, well, pot after alleging that pot smokers' tongues turn green after a smoke session. USA Today says there's even one training program that tells officers to "look for a possible green coating" on a suspected toker.
Here's the thing: there's no scientific evidence that a marijuana smoker's tongue ever turns green. There are some people who've been fighting this myth for decades after cops used it in affidavits to arrest and charge them with things like speeding. 28 cases alone in York County, Pennsylvania mention "green tongue" in the affidavits.