Diet and Drug Tests: What foods make you test positive for opioids?

October 9, 2025 •

4 min read

According to the US Anti-Doping Agency, consuming poppy seeds can lead to a positive drug test for morphine and codeine, with these compounds remaining detectable in urine for up to 48 hours. Understanding what foods make you test positive for opioids? is crucial, as certain dietary choices can trigger a false positive result on standard drug screenings.

Quick Summary

Certain foods, primarily poppy seeds, can lead to false positive drug test results for opioids due to trace contamination with morphine and codeine during harvesting. Awareness of this risk is important for those undergoing drug screenings, as timing and quantity of consumption are key factors. Confirmation testing is needed to distinguish between legitimate opioid use and dietary exposure.

Key Points

Poppy Seeds are the Culprit: The seeds from the opium poppy plant can become contaminated with trace amounts of morphine and codeine during harvesting, leading to false positive opioid drug tests.
Detection Window is Limited: Opiates from poppy seed consumption can be detected in urine for up to 48-60 hours, with a positive result possible even after eating just one bagel.
Higher Cutoffs Help, but Don't Eliminate Risk: Increases in drug testing cutoff levels by the DHHS have reduced, but not eliminated, the risk of a false positive from poppy seeds, as some clinical tests still use lower thresholds.
Confirmatory Testing is Key: Confirmatory tests, such as Gas Chromatography–Mass Spectrometry (GC–MS), can provide more precise results and help distinguish dietary ingestion from intentional drug use.
Avoidance is the Safest Bet: The most reliable way to prevent a false positive from food is to completely avoid all products containing poppy seeds for several days before a drug test.
Specific Markers Distinguish Heroin Use: The presence of the metabolite 6-monoacetylmorphine (6-MAM) can definitively confirm heroin use, distinguishing it from poppy seed contamination.
Other Foods Can Cause Different False Positives: Other foods and substances like hemp seeds, coca tea, and fermented items can cause false positives for other drug classes.

The Poppy Seed Problem: Opioid Contamination

Poppy seeds, a common ingredient in baked goods like bagels, muffins, and pastries, are the most notorious food linked to false positive opioid test results. The seeds themselves do not naturally contain opioids, but they are harvested from the opium poppy plant, Papaver somniferum. During harvesting, the seeds can become contaminated by the plant's milky sap (latex), which contains various opioid alkaloids, including morphine and codeine. Despite thorough cleaning processes, trace amounts of these compounds can remain on the seeds.

When ingested, these trace amounts are enough to be detected by the sensitive immunoassays used in standard drug screenings, particularly urine tests. The concentration of opioids on the seeds varies based on factors like the poppy variety, geographic origin, and processing methods. As a result, there is no definitive 'safe' amount of poppy seeds that guarantees a negative test, making avoidance the most conservative strategy before a drug screening.

Factors Influencing False Positive Results

Several variables determine whether poppy seed consumption will lead to a false positive test for opioids:

Quantity consumed: Eating a large amount of poppy seeds, such as multiple bagels or a rich lemon-poppy seed cake, significantly increases the likelihood of a positive test. However, even smaller amounts can trigger a false positive, depending on the test's sensitivity and the seed's level of contamination.
Test sensitivity and cutoff levels: The cutoff concentration for what constitutes a 'positive' result can vary between testing labs. In 1998, the U.S. Department of Health and Human Services (DHHS) increased the opiate cutoff level from 300 ng/mL to 2000 ng/mL to reduce false positives from poppy seeds, though some clinical settings may use lower thresholds. Immunoassay tests, which are typically used for initial screenings, are more prone to cross-reactivity with foods than confirmatory tests like Gas Chromatography–Mass Spectrometry (GC–MS).
Individual metabolism: A person's metabolic rate and the speed at which their body processes and eliminates these compounds also play a role. Opiates from poppy seeds can be detectable in urine for up to 48-60 hours after ingestion, depending on the amount consumed.

Other Potential Food-Related False Positives

While poppy seeds are the most direct food-related cause of false opioid positives, other substances can interfere with drug tests, though generally not for opioids specifically. Awareness of these is part of a comprehensive understanding of drug testing protocols.

Hemp seeds and products: Can lead to false positives for THC (cannabis) due to trace amounts of cannabinoids.
Fermented foods and beverages: Kombucha, sauerkraut, and soy sauce can produce low levels of ethanol, potentially triggering a false positive for alcohol metabolites.
Certain herbal teas: Coca tea contains actual coca alkaloids, which break down into cocaine metabolites and can result in a positive test for cocaine.
Quinine: Found in tonic water, this can sometimes lead to an inaccurate opioid reading on some screening tests.

Distinguishing Poppy Seed Ingestion from Illicit Use

Laboratories use various methods to differentiate between food-related contamination and actual opioid use. Standard urine immunoassay screens for opioids (morphine and codeine) may trigger a positive result from poppy seeds. However, advanced confirmatory testing, such as GC-MS, is more precise. Some studies suggest that the ratio of codeine to morphine can be used to distinguish poppy seed consumption from codeine medication, though recent research has challenged this theory. Another marker, 6-monoacetylmorphine (6-MAM), is a specific metabolite of heroin, and its presence confirms heroin use, distinguishing it from poppy seed ingestion.


Feature	Poppy Seed Contamination	Opioid Drug Use
Opioid Source	Trace alkaloids from the Papaver somniferum plant.	Pharmaceutical (prescription) or illicit drugs.
Morphine/Codeine Levels	Generally lower, though can exceed screening cutoffs.	Often higher, depending on dosage.
6-MAM Metabolite	Absent.	Present if heroin is used.
Detection Window	Typically 48-60 hours after consumption.	Varies by drug and use frequency.
Confirmatory Testing	Can confirm low levels or distinguish ratios.	Confirms the presence of specific drugs and metabolites.

How to Avoid a False Positive

If you have an upcoming drug test, especially in a workplace, military, or clinical setting, it is wise to take preventive measures regarding your diet:

Avoid poppy seeds completely: Do not consume any food products containing poppy seeds for at least 3-4 days before your test. This includes bagels, muffins, rolls, salads, and dressings. A 2023 Department of Defense memo explicitly warned military service members to avoid all poppy seeds.
Communicate your diet: If you have recently consumed poppy seeds and have a positive result, inform the testing professional. They can take this into account and may order a more specific confirmatory test.
Read ingredient lists: Always check labels for products that may contain poppy seeds or hemp seeds, even if it's not obvious from the name.
Stay hydrated: Drinking plenty of water can help flush your system, though it is not a guaranteed way to pass and over-diluting a sample can also be problematic.

Conclusion

For anyone facing a drug test, being aware of how certain foods can lead to a false positive result for opioids is a necessary precaution. The primary culprit is the humble poppy seed, which can carry trace amounts of morphine and codeine from the harvesting process. While the risk of a false positive from consuming common poppy seed products is not a certainty, avoiding them entirely in the days leading up to a test is the safest course of action. If a positive result occurs, especially in a professional context, it's essential to understand the potential dietary cause and seek confirmatory testing to resolve the issue fairly. For more information on drug testing protocols and false positive causes, consult authoritative resources like the National Institutes of Health.

Frequently Asked Questions

Opiates from poppy seeds can typically be detected in urine for up to 48 to 60 hours after consumption, with detection time dependent on the quantity consumed and individual metabolism.

Yes, even a single poppy seed bagel or muffin has been shown in studies to potentially cause a positive urine drug test for opiates, especially with older, more sensitive tests.

The primary substances are morphine and codeine. During harvesting, the seeds can be coated with the latex from the opium poppy plant, which contains these natural opioid alkaloids.

While initial immunoassay tests may not differentiate, confirmatory tests like GC-MS and analysis for specific metabolites like 6-monoacetylmorphine (6-MAM) can distinguish between poppy seed consumption and the use of actual drugs like heroin.

No, the level of opiate contamination varies significantly depending on the variety of poppy plant, geographic origin, and processing methods used during harvesting.

Yes, avoiding all products containing poppy seeds for at least 3-4 days before a test is the most reliable way to prevent a false positive result.

No, the trace amounts of opiates in commercially sold poppy seeds are not enough to cause a pharmacological effect or to make a person feel high.