It sounds like a flimsy excuse. But poppy seeds really can make you fail a drug test, both peer-reviewed scientific studies and unofficial experiments conducted by journalists have found. Because they’re derived from opium poppies, they sometimes contain traces of morphine -- not enough to get you high, obviously, but potentially enough to register on a highly sensitive drug test.That’s what a Maryland mother says happened to her back in April when she went to the hospital to give birth.Elizabeth Eden told WBAL-TV on Monday that she’d eaten a poppy seed bagel on the same morning that she went into labor. While she was having contractions, a doctor came into her hospital room and informed her that she’d tested positive for opiates.Recalling having heard that poppy seeds could result in a false positive, she asked the doctor to test her again, she said. According to her account, he refused, and reported her to state officials."It was traumatizing," she told the station.The positive test result meant that her daughter had to stay in the hospital and be monitored for five days. Afterward, Eden was assigned a case worker who closed her file after determining that she was "a legitimate case of the poppy seed defense," WBAL-TV reported.Surprisingly, her experience isn’t unique.In October 2010, the American Civil Liberties Union of Pennsylvania filed a lawsuit on behalf of a woman who had her 3-day-old daughter taken away by child welfare officials for five days after she ate a poppy seed bagel and failed a drug test. They alleged that Jameson Hospital in New Castle, Pennsylvania, had used a threshold that was significantly lower than what the federal government requires for workplace drug testing, and also had failed to ask the woman whether she had eaten anything that might have affected the test results. The hospital and county ultimately settled for $143,500 and agreed to change their policies.A similar lawsuit against the same Pennsylvania county -- filed by a woman whose newborn son spent 75 days in foster care after she ate pasta salad with a poppy seed dressing -- settled for $160,000 the following year.Twenty years ago, the likelihood that a poppy seed bagel would register as a false positive prompted the federal government to revise its policies for workplace drug testing.Before the guidelines were updated in 1998, individuals whose urine tests showed morphine concentrations of over 300 nanograms per milliliter were considered to have tested positive for opiates."These levels were selected in an attempt to provide the greatest opportunity to identify anyone who may have used heroin; however, at the 300 ng/mL level, many who have not used heroin but had taken a prescribed codeine or morphine medication or eaten normal dietary amounts of poppy seeds have also tested positive," explained a notice in the Federal Register.The Department of Health and Human Services raised the limit to 2,000 nanograms per milliliter -- meaning, according to one forensic scientist who the New York Times interviewed, that you could eat three large poppy-seed bagels and still pass the test.But some hospitals still use the lower cutoffs when testing new and expectant mothers. St. Joseph Medical Center, where Elizabeth Eden gave birth, screens for 300 nanograms per milliliter, since some drug users might test negative otherwise, Judith Rossiter-Pratt, the head of the obstetrics and gynecology department, told WBAL-TV.And not all human resources departments follow the precedent set by the federal government.In January 2016, Eleazar Paz, a New York City jail guard, was suspended from his job after he failed a random urine test that showed he’d tested positive for 522 nanograms per milliliter of morphine and 358 nanograms per milliliter of codeine. According to court documents, he later recalled that he’d had eggs, a poppy seed bagel, coffee, and orange juice for breakfast that day.Paz was suspended from his job, then reinstated on modified duty after a hair follicle test and a second urine test came back negative. In April 2018, when his case went to trial before the city’s Office of Administrative Trials and Hearings, an expert toxicologist testified on his behalf, arguing that the bagel was to blame and that someone who abused morphine and codeine would "have urine values in the thousands."The toxicology expert, William Sawyer, also "expressed surprise" that the New York City Department of Corrections was continuing to use the 300 nanogram per milliliter cutoff, court documents say.Concluding that "the most likely source of the positive morphine and codeine test results was the ingestion of poppy seeds and not the use of medications," Judge John B. Spooner issued a report in June recommending that the disciplinary proceedings against Paz be dismissed.But on Tuesday night, the New York Post reported that the Department of Corrections had ignored the judge’s recommendations, and fired Paz anyway."We are surprised and disappointed at the commissioner’s decision," Paz’s lawyer, Andrew Grossman, told the paper.Department of Corrections officials couldn’t immediately be reached to confirm or comment on Paz’s firing late Tuesday night, but told the New York Post, "There is no real evidence that a few poppy seeds can make you fail a drug test."While it may be true that "a few" poppy seeds won’t necessarily result in a failed drug test, it’s nearly impossible to find a definitive answer about how many poppy seeds is too many. The amount of morphine residue on poppy seeds can vary, depending on how they were cleaned and processed, and what country they came from. For that very reason, the U.S. Anti-Doping Agency’s website tells Olympians that "[t]he most conservative approach would be to avoid poppy seeds a few days before and during competitions."Similarly, the Federal Bureau of Prisons requires inmates who leave on temporary furloughs to promise that they won’t consume any poppy seeds whatsoever."It has been determined that consumption of poppy seeds may cause a positive drug test which may result in disciplinary action," the application form given to prisoners reads. "As a condition of my participation in community programs, I will not consume any poppy seeds or items containing poppy seeds."There may be hope for bagel enthusiasts: The Washington Post’s Maura Judkis reported in June 2017 that a British specialty foods company has developed a low-morphine poppy seed that won’t show up on a drug test. Until those become widely available, however, you may want to stick with sesame.