Poppy seeds are a common ingredient in many baked goods, pastries, and savory dishes. These tiny, edible seeds come from the opium poppy plant, Papaver somniferum, which is also the source of pharmaceutical opiates. While the seeds themselves are not psychoactive, consuming them can trigger a positive result on a drug screening test for opiates.
Identifying the Source of the False Positive
The poppy seeds themselves do not naturally contain the opiate compounds that drug tests screen for. The seeds are harvested from the mature seed pod of the opium poppy, which contains a milky latex sap rich in alkaloids. During the harvesting process, the seeds can become contaminated with this raw opium latex, coating their outer surface.
The two primary compounds that cause a positive test result are morphine and codeine. These are the specific opiates targeted by drug panels. The level of contamination—the amount of residue on the seeds—varies widely based on the poppy variety, geographic origin, and processing methods. Commercial poppy seeds typically undergo washing and heat-processing to significantly reduce contamination before packaging. However, this processing does not remove all opiate residue, and unwashed or minimally processed seeds retain a much higher concentration of alkaloids.
Understanding Test Sensitivity and Cutoffs
Drug screenings rely on established cutoff levels to distinguish between drug use and incidental exposure. A test result is only considered positive if the concentration of the drug or its metabolites in the urine exceeds a predetermined threshold, measured in nanograms per milliliter (ng/mL). The Substance Abuse and Mental Health Services Administration (SAMHSA) sets guidelines for federal workplace drug testing programs, and these cutoffs have been adjusted over time to account for poppy seed ingestion.
The standard laboratory cutoff for opiate confirmation in urine was 2,000 ng/mL for morphine and codeine. Studies showed that consuming large amounts of contaminated poppy seeds could push morphine concentrations above this level. To reduce the risk of false positives, SAMHSA raised the confirmatory cutoff for morphine to 4,000 ng/mL, while keeping the codeine cutoff at 2,000 ng/mL. Specialized laboratories can also test for the presence of thebaine, another poppy plant alkaloid, which helps differentiate poppy seed consumption from the use of prescription or illicit opiates.
Preparing Seeds and Safe Consumption Levels
For individuals subject to mandatory drug testing, the most conservative advice is to avoid poppy seeds entirely for several days before a test. However, for those who wish to consume them, the processing of the seeds before consumption can significantly reduce the alkaloid content. Simple washing or soaking with water can reduce morphine levels by 40% to 75%, and using hot water has been reported to be even more effective.
Further food processing, such as grinding or baking, also decreases the opiate alkaloid content, with reductions reported up to 90%. When poppy seeds are baked into items like bread or muffins, the heat helps to degrade the alkaloids. Despite these mitigation methods, there is no universally defined “safe consumption level” because the initial contamination of raw seeds varies drastically. Even a single portion of a highly contaminated poppy seed product can potentially lead to a positive result, and the levels can be detected in urine for up to 48 hours after consumption.