Although the drug opium is produced by "milking" latex from the unripe fruits ("seed pods") rather than from the seeds, all parts of the plant can contain or carry the opium alkaloids, especially morphine and codeine. This means that eating foods (e.g., muffins) that contain poppy seeds can result in a false positive for opiates in a drug test.
This was considered "confirmed" by the presenters of the television program MythBusters. One participant, Adam Savage, who ate an entire loaf of poppy seed cake, tested positive for opiates just half an hour later. A second participant, Jamie Hyneman, who ate three poppy seed bagels, first tested positive two hours after eating. Both tested positive for the remainder of the day, but were clean eighteen hours later. The show Brainiac: Science Abuse also did experiments where a priest ate several poppy seed bagels and gave a sample, which also resulted in a false positive.
Tou um bocado a morder os cantos da minha mesa de trabalho...