The urban legend that eating poppy seeds can lead to a failed drug test is, in fact, not a legend. Eating poppy seeds – even as few as are typically contained in a large Costco poppy seed muffin – can yield positive test results for both morphine and codeine when testing standards are not adjusted to weed out such “false” positives.
 
Poppy seeds, morphine, and codeine all naturally occur in the opium poppy plant, Papaver somniferum. Accordingly, poppy seeds like those used in muffins, bagels, breads, and pastries, contain the opiates codeine and morphine. The opiate content of poppy seeds varies greatly based on the seed origin, when the seeds are harvested, and how the seeds are processed from harvest to consumer. Opiate concentration is also affected by how seeds are ultimately consumed: raw, ground into a paste, sprinkled atop a bagel, baked whole into a cake or muffin, etc.
 
Multiple published, peer-reviewed, scientific studies have shown that ingestion of poppy seeds can result in urinary concentrations of morphine and codeine detectable in standard drug tests used by certain workplaces. Though many workplace drug tests have adjusted their laboratory standards to avoid “false” positive results caused by ordinary poppy seed consumption, it is still possible to test positive for illicit opioid drugs when lower cutoffs are used.
 
In 1998, the Federal Department of Health and Human Services Substance Abuse and Mental Health Services Administration revised their mandatory guidelines for federal workplace drug testing programs due to concerns that many positive opiate tests were the result of poppy seed consumption. While the previous urine sample testing cutoff levels for both morphine and codeine previously were 300 ng/mL (nanograms per milliliter), the Department of Health and Human Services increased the cutoff levels for both opiates to 2,000 ng/mL, effective May 1, 1998.
 
If you know you will be required to provide a urine or other biological sample for drug testing, it is prudent avoid consuming poppy seeds for at least one day prior to giving the sample.