Health Library

True or False: Eating Poppy Seed Pastries Can Lead To a Positive Drug Test for Heroin

mythbuster graphic Drug testing is becoming more and more common in our society, and false positive results can have a devastating impact on an innocent person’s career. Have you heard rumors that eating poppy seed pastries can cause positive test results for heroin? It’s true! Opiates (such as heroine, morphine, and codeine) can be found in urine samples for as long as two days after eating poppy seed-containing foods, and for up to 60 hours if large quantities of the seeds are consumed. Hair analysis is a more accurate, but less commonly used method of testing for recent heroin use: in a hair analysis, a false positive test would not occur after eating poppy seed pastries.

Evidence for the Health Claim

Heroin is a derivative of morphine, the active ingredient in opium which is obtained from the opium poppy. Heroin also contains acetylcodeine, which your body converts to codeine. Traces of both morphine and codeine can also be found in the poppy seeds which are commonly used as ingredients in a variety of baked goods.

Until December 1, 1998, the National Institute on Drug Abuse (NIDA) had set the cut-off concentration level for opiate urine tests at 300 ng/ml for the Federal Workplace Drug Testing Program. But this standard urine screening was not able to reliably differentiate between poppy seed eaters and opiate users based on concentration levels of opiates. That’s because eating a poppy seed bagel will produce an opiate level of approximately 250 ng/ml three hours later, and ingesting three teaspoons of poppy seeds can result in a level of 1,200 ng/ml six hours later.

Studies have been conducted worldwide to verify the validity of what has been called “the poppy seed defense.” In a variety of studies, subjects have shown initially negative test results for opiates, followed by positive results only a few hours later after having consumed cakes, rolls, muffins, bread, or bagels containing poppy seeds.

One high-profile demonstration of the validity of poppy seed drug test claims was conducted by the Discovery Channel television program called "Mythbusters." One participant ate a poppy seed cake and tested positive for opiates a ½-hour later. The other participant ate three poppy seed bagels and tested positive two hours later. Both parties continued to test positive for 16 hours.

The Department of Health and Human Services (DHHS) conducted a study that examined the results of 317,500 urine specimens that were tested for opiates and reviewed by three Medical Review Officer (MRO) groups, as well as 1.1 million specimens from five certified laboratories. The MRO’s reportedly reversed 87% of all the positive urinalysis test results due to false positives attributed to poppy seed ingestion, prescription medication, or other reasons.

The laboratory results showed that approximately 81% of the specimens that tested positive for codeine and morphine had concentration levels under 2,000 ng/ml. As a result, NIDA guidelines have been amended and cut-off levels for opiates have been increased to 2,000 ng/ml. The US military has set the cut-off level at 3,000 ng/ml to avoid false positive results.

Evidence Against the Health Claim

Hair analysis is a more accurate means of testing for heroin use as it is impossible for poppy seed ingestion to produce a false positive result. That’s because the opioid in poppy seeds does not stay in the bloodstream long enough or in high enough concentrations to be trapped inside hair follicles in measurable quantities.

Also, heroin can be best identified by the presence of the distinct heroin metabolite called 6-O-monoacetylmorphine (6-MAM). The new NIDA guidelines require testing for the 6-MAM metabolite in urine. However, heroin is metabolized quickly in the body, so 6-MAM’s presence can only be detected through a urine test on the same day that a person used heroin. This makes the likelihood of identifying heroin users through urine testing very poor. But 6-MAM is identifiable in the hair for months.

Recently there has been extensive research on the use of saliva in drug testing. The advantage is obvious, as the ease with which a sample can be collected makes it a really attractive for testing. Oral fluid drug testing is already used in the transportation and insurance industries. It will likely be introduced in the other places, as well. The major disadvantage of such testing is that it does not provide historical information about drug usage, as drugs disappear from saliva within hours of usage.


Some organizations have decided not to take any chances with poppy seeds and drug testing. Federal prisons do not allow prisoners to eat poppy seeds and require prisoners to sign a form agreeing to abstain from eating poppy seed products while taking authorized leaves of absence. Because different organizations may use different guidelines for testing, before you take a drug test, think about your recent poppy seed consumption. Maybe today is a good day to try a sesame seed bagel!


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Image Credit: Nucleus Communications, Inc.