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12 Common Household Products and Foods that can Cause False Positive Drug Tests

Did you know there are commonly-found household products and foods that can cause false positive drug tests?

foods that can cause a false positive drug test

As a student or professional, there comes a time when you have to provide a urine sample for drug testing. Let’s assume you’re a strong candidate for your dream job and the interview panel is demanding a drug test before they can hand over the contract.

You gladly and confidently oblige knowing very well that you have not used any illicit drugs.

After a few days, the drug test results are delivered and you’re called in to discuss your future with the new company. To you, this is good news since you’re sure of what to expect. But the spring in your step quickly turns to a limp as you read the words “tested positive for drugs A and B.”

As you stand there in dismay, you try to recall a time when you might have ingested even a speck of an illicit drug—but nothing comes to mind. You wonder, “How can you fail a drug test without doing drugs?”

As dramatic as this sounds, it’s actually a reality for a surprisingly large number of people. According to a report presented to the American Psychiatric Association (APA), up to 1 in every 10 drug tests are likely to be false positives.

Below we outline what can cause a false positive, how to dispute an incorrect drug test result, and the steps to take if the test is in fact accurate.

Drinks and Foods that Can Cause a False Positive on a Drug Test

Believe it or not, the cause of a failed drug test might be a seemingly harmless everyday product lying around in your kitchen. Some foods, drinks, and prescription medications contain the necessary chemicals and metabolites to trigger a false-positive.

foods to avoid before drug test

Poppy Seeds

If a poppy seed bagel is part of your morning routine, it might be best to break the tradition if you have an upcoming drug test.

These tiny black seeds turn out to be one of the foods that cause a false-negative drug test. In fact, some U.S. government agencies explicitly discourage the consumption of poppy seeds before a drug test. Here’s why:

The crunchy little seeds people sprinkle over cakes, cookies, and bagels come from the Papaver somniferum plant, or the opium poppy, which is also used to make heroin. Although the seeds are harmless, they contain trace amounts of codeine and morphine (around 0.5-10 micrograms per gram).

This opiate concentration is far from anything that could get you high, especially when considering that medically-prescribed morphine has a concentration of 5,000-30,000 micrograms/gram.

However, sometimes drug tests can’t differentiate poppy seeds from other more potent and illicit opiates. The World Anti-Doping Agency code recommends a morphine threshold of 1.3 micrograms per gram. Similarly, the U.S. federal government maintains a threshold of 2 micrograms/gram.

And as evidenced by a study in the Journal of Analytical Toxicology, there’s a chance for a false positive drug test from eating poppy seeds.


For most people, pizza is the epitome of culinary achievement. The gooey cheese, generous toppings, savory sauce, and crispy crust are enough to make anyone drool. It’s a food that is admired and celebrated across the world—transcending cultural boundaries.

According to a study published in PLoS One journal, this universal love for pizza may be associated with indicators of addiction.

Pizza addiction aside, one breathalyzer manufacturer notes that the food can be the reason behind a false positive on a drug test. How so? Yeast promotes the fermentation of sugars into alcohol and other substances—hence causing the dough in your pizza or any other pastry to rise.

Although you should not expect to feel tipsy after eating a slice (or four) of pizza, the alcohol in your mouth might be just enough to return a false positive drug test result. If you can’t keep off the pizza before a drug test, at least rinse your mouth after you’re done.


Few fruits if any are as divisive as the durian (aka The King of Fruits). The Asian fruit is admired and repulsed in equal measure. For some, its nutritional value, unique flavor, and custardy texture make for a great snack. For others, the pungent smell it emanates when ripe is simply unbearable.

Fun fact: Durian fruit caused a commotion in an Australian University after its odor was mistaken for a gas leak.

In addition to the relatively offensive stench, the prickly Asian fruit also happens to be one of the foods that can cause a false positive drug test.

In a 2019 incident reported by the BBC, a Chinese man was stopped by police officers in the Jiangsu Province for suspected drunk driving. Following a breathalyzer test, the officer concluded that the man was indeed drunk despite his objections.

A follow-up blood test proved otherwise—prompting the law enforcers to try the durian themselves. The outcome was a breathalyzer blood-alcohol level of 0.016% above the legal limit in China. This was attributed to “mouth alcohol” that lingers briefly after eating ripe fruit.

Hemp Seeds – Granola Bars

When President Trump signed the 2018 Farm Bill (Agriculture Improvement Act of 2018), he legalized the production of hemp at the federal level. Hemp is a breed of the Cannabis Sativa L. plant—but with a THC (psychoactive compound in marijuana) concentration of less than 0.3%.

This established hemp and hemp seeds as a regulated commodity with significant industrial applications. This also means that there is a good chance that hemp seeds mind end up in your diet or products – case in point, granola bars and hemp oil.

The trace amounts (<0.3%) of THC (tetrahydrocannabinol) in hemp are not enough to cause intoxication. But the psychoactive ingredient may accumulate in your body’s fat cells and linger for up to 5 weeks.

If you consume hemp seeds frequently, they might turn out to be your answer to the question; “How can you fail a drug test without doing drugs?”

A Cup of Coca Tea

Still wondering how you can fail a drug test without doing drugs? Try drinking coca tea right before submitting your sample. Although not widely popular in the United States, coca tea is a delicious drink that’s derived from the same source as cocaine—coca leaves.

Drawing from the results of a 2016 study appearing in the European Journal of Emergency Medicine, the beverage is broken down to form cocaine metabolites—which might result in a false positive.

According to the researchers, traces of the metabolites can be identified in as little as 2 hours and remain in the system for up to 36 hours.

Tonic Water

Another drink that can cause a false positive drug test is one that’s easy to overlook—tonic water. Originally, tonic water was sold and drank for its quinine content (Ps: Quinine is an anti-malaria drug derived from the cinchona tree in South America).

Fast forward to more recent times, quinine is commonly used to cut illicit drugs such as heroin. For this reason, your urine after drinking a bottle of tonic water might reflect that of a drug user.

Some studies show that this association of quinine with street drugs might raise alarms during your urine test—leading to false positive drug tests.

What Can Cause a False Positive on a Drug Test Aside from Food?

Food and drinks are not the only culprits for a failed drug test. Some over the counter medication and even soap might be your source of distress.


Ibuprofen is a common nonsteroidal anti-inflammatory drug (NSAID) that helps reduce pain, fever, and inflammation.

In rare cases—as shown in a study published in the Journal of Clinical Chemistry— there is a “small likelihood of a false-positive immunoassay test result for cannabinoids, benzodiazepines, or barbiturates after the acute or chronic ingestion of ibuprofen.

The general rule of thumb is to conduct additional screening tests in case a patient claims to be using ibuprofen.


Certain antibiotics such as fluoroquinolones and rifampin have also been shown to cause a false positive on a drug test.

In a 2002 Lebanese case, a 7-year old boy admitted to the American University of Beirut Medical Center tested positive for opiates following a urine test.

After a careful re-examination of the case, the medical team determined that “the interfering substance in this positive opiate screen was suspected to be rifampin.”

Cold Medication

How can you fail a drug test without doing drugs? Well, it depends on the type of drug you’re referring to. While you may not have abused an illegal drug, the antihistamine you bought in your local pharmacy when you were under the weather could cause a false positive.

Common antihistamines such as levomethamphetamine (used in inhalers) and brompheniramine (cold and allergies) have been shown to be “mirror images” of methamphetamine. Using the over the counter medication puts you at risk of failing a drug test.

Passive Weed Smoking

You could fail a drug test by virtue of being in the same room with weed smokers, but usually only in extreme cases. According to a study published in the Journal of Analytical Toxicology, you would have to be locked in a room with no ventilation and sit next sit to a group of around 6 smokers to test positive for THC.

The researchers concluded, “These results demonstrate that extreme cannabis smoke exposure can produce positive urine tests at commonly utilized cutoff concentrations. However, positive tests are likely to be rare, limited to the hours immediately post-exposure, and occur only under environmental circumstances where exposure is obvious.”

Antiretroviral Medication

In a 2006 study appearing in the Journal of Therapeutic Drug Monitoring, the researchers discovered that 100% of respondents who took Sustiva—an HIV medication containing efavirenz—tested positive for THC.

These findings were later supported by another similar study in 2009 in which 98% of subjects who took efavirenz tested positive for marijuana and benzodiazepines. It appears that the antiviral medication interferes with the accuracy/workings of the urine tests.

Baby Soap

To cap off the list of products and foods that can cause false positive drug tests is the most unsuspecting culprit—baby soap.

To quote a study published in the Journal of Clinical Biochemistry, “commonly used soap and wash products used for newborn and infant care as potential causes of false positive THC screening results.”

Some of the baby soaps observed in the study include Aveeno Wash Aveeno Soothing Relief Creamy Wash Shampoo, CVS Night-Time Baby Bath, J&J Bedtime Bath, and Johnson & Johnson’s Head-to-Toe Baby Wash.

And since a positive marijuana drug test could lead to accusations of child abuse or involvement of social services, it’s important to understand the risk of false positives.

Please note that this does not mean the babies can be intoxicated the soaps nor are there effects associated with marijuana.

How to Dispute a False Positive on a Drug Test

If you happened to fall victim to the above foods, it’s important to learn how to dispute a false positive drug test.

If you’re sure that you’ve not consumed any alcohol or illegal drug as insinuated in the false positive drug test results, the first step is to request additional tests for verification. This often calls for blood screening to confirm the results.

In the case of alcohol tests, simple blood tests may prove your innocence—since alcohol from foods rarely enters the bloodstream.

For other substances such as ibuprofen and cold medication, advanced tests such as High-Performance Liquid Chromatography (HPLC test) or Gas Chromatography-Mass Spectrometry (GC-MS test) are used. These tests separate the elements in your urine sample and mark them to identify possible interference.

If you’re able to successfully dispute a false positive drug test, you could potentially salvage a job or even avoid legal charges.

What If you Actually Failed the Drug Test?

Sometimes the results have nothing to do with foods that cause false positive drug tests. They might be genuine with no interference. This may point to do a drug and alcohol problem that needs professional intervention and care.

Addiction is a multi-faceted illness that not only impacts the individual but his/her family and people around. The repercussion of substance abuse may be far reaching and beyond just a failed drug test. It’s important to note that drug dependency is often a gradual process that slowly creeps in until you no longer have control.

If you’re struggling with addiction, it’s highly advisable and never too late to seek professional help and take back control of your life.

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