This partially true, but exaggerated, legend has been featured in several movies and television shows, such as "Seinfeld" and "The Big Bang Theory". Poppy seeds do contain trace amounts of opium alkaloids, including morphine. Poppy seed-filled "pastries" (such as hamantashen or kolaches), contain enough opiates to potentially cause a false positive test result, even when a fairly high cutoff level is used. However, drug tests rarely screen for the actual drug used; instead they detect metabolites or increased enzyme levels as markers indicative of drug use. When substance use has been established (and the drug type, i.e. opiate or amphetamine), one can then be tested to identify the specific substance by means of more expensive Gas Chromatography drug screens.