Jacob Sullum reads a new report by the Marijuana Policy Project on faulty marijuana tests:

...the report found that "patchouli, spearmint, and eucalyptus tested positive for marijuana, while lavender, cypress, and oregano (which previous studies showed produced false positives with the D-L test) gave inconclusive results." In tests using just the NarcoPouch KN Reagent kit, 33 of 42 substancesincluding vanilla, anise, chicory, and pepperminttested positive for cannabis.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.