Fact Checked

What Could Cause a False Positive on a Drug Test?

Malcolm Tatum
Malcolm Tatum
Malcolm Tatum
Malcolm Tatum

With many employers making use of random drug testing in the work place, employees sometimes wonder about the possibility of registering a false positive on a drug test. The fact is, there are a number of different over-the-counter medications, foods, vitamin supplements, and even prescription medicines that can cause a false positive. It's important for employees to let their employer and the testing facility know if they have taken any medicines that might affect the results.

Among over-the-counter medicines, many of the night-time cold medications people use to minimize cold and flu symptoms for the evening can cause false positives. This is particularly true of the liquid cold relievers, as many of them contain various members of the ephedrine family. Some weight loss products also can cause false positives, as can some nasal sprays and asthma medications.

Poppy seeds can skew drug testing results by showing up as an opiate.
Poppy seeds can skew drug testing results by showing up as an opiate.

Certain foods can sometimes result in a false positive on a drug test. Many people are familiar with the fact that poppy seeds can throw off the results by showing up as an opiate. These seeds are often used in salad dressings, as an ingredient in many casseroles, and as an added topping on buns and rolls.

Vitamin supplements may also cause a false positive. Riboflavin, also known as B2, may return a false THC reading. Along with being part of most B complex vitamin supplements, riboflavin is found in hempseed oil and also as a stand alone supplement. Many herbs that contain moderate to high amounts of B vitamins may also register a false positive on a drug test.

Many employers conduct random drug testing on their employees.
Many employers conduct random drug testing on their employees.

Prescription medications, including antibiotics like ampicillin and amoxicillin, can cause problems as well. Many prescription pain medications will show up on a drug test since they can contain ingredients that are related to some illegal drugs. Even some anti-anxiety medications can cause a positive result. Some diseases, such as diabetes, liver disease, and kidney infections, may even register as opiates on drug tests.

Amoxicillin can cause problems on a drug test.
Amoxicillin can cause problems on a drug test.

When preparing for a drug test, individuals may want to provide a list of any medications taken recently, as well as vitamins and any herbal supplements, to the testing facility and the company's human resources department. If the person undergoing the drug test has an ongoing medical condition, that information should be provided also. This can make a huge difference in evaluating the final results of the test.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including , and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including , and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Discussion Comments


Are there any herbs vitamins or supplements that would make you drug test positive for suboxene?


I take MS Contin 100 and Morhpine 30, yet my tests showed only trace amounts. Is this possible?


I am a former mass transit train operator due to a false marijuana drug test. Prior to the test I had a root canal done. I took some prescription Ibuprofen 2 600mg tabs and got tested the very next day. It was a DOT test that tested at 50ng and above. About four days later the MRO called me and said I tested positive for marijuana and my level was 101. He then asked when was the last time I smoked. I replied by saying I don't smoke. This was on a Thursday and on Monday I took my own personal test and tested negative -- and this test detects drug use at an 0.3 level and I still was fired.

I am so confused about all of this. I would not risk my good-paying, random testing job for no illegal drug. What can I do about this? My Union is not standing behind Me.


I am currently disabled and wearing Fentanyl patches and taking morphine sulphate. For the last couple of months, my urine tests have been coming up inconsistent. The first one showed positive in the office for oxycodone in the office. They sent it to the lab and I showed positive for oxymorphone. So the next time I visited the doctor they tested me again and again I showed positive for oxycodone in the office. I don't take oxycontin, oxycodone, oxymorphone or any illegal drugs and of course my doctor had that look of intense disappointment when I left the office.

So the next morning, I went right out to a different lab and had my urine tested. Well, it came out clean but it didn't even pick up my morphine sulphate so the test was still incorrect. It seems that an awful lot rides on the assumption that these tests are accurate. How is that possible? What would be causing my tests to mess up this bad?


What about diet pills? Would those test positive?


I recently had a five panel test that tested positive for meth and the same day had a twelve panel that tested negative.

I know that I haven't used. When they send it to to the lab they will be able to tell that, right? My life is in jeopardy and I need some answers. Please help!


I smoked cannabis and then showed up positive for THC in a urine test. How can they put so much stock in such inaccurate tests! I almost lost my job over it.


I take different over the counter meds and herbal supplements with vitamins. What would test a false positive for Suboxone?


I have recently failed a hair drug test for THC. I don't smoke cannabis, I have taken strong vitamin b tablets containing riboflavin 2mg. Could this be why?


I am on methadone, so this is the only medication I have been taking. I've been clean of everything for three and a half months, but a few days ago, I came up dirty on drug test for cocaine and benzos.

I haven't done cocaine for over three months and have never in my life done a benzo.

I asked for another test, so this one taken tow days ago comes up dirty for weed and benzos.I smoked weed like three times almost 15 years ago, and like I said already, I've never done any benzos, ever. I don't take over the counter medicines, prescribed medicines or street drugs. What's the problem? Why am I showing these dirty urine samples when I haven't touched anything other than my methadone that I go to the clinic daily to take?


@anon148890: Not to call your daughter a liar, but how do you know for certain she didn't use anything? Suboxone is to takes away withdrawal pains of heroin. I am on Methadone from being on heroin, so I can tell you anyone who is a heroin addict is a great liar. Hopefully she is clean, but I would definitely look into it a little more. I'd hate to see you overlooked something when your daughter needs some help.


@aAnon38644: You are positive for meth because some over counter medicines like sudafed and nyquil show up for methamphetamines. It doesn't always show up positive in a drug screen, but sometimes does.


No it is not stereotyping when you give a drug test and then don't treat the person with medication because of the outcome.

It is not safe to take medications with other drugs or medicines in your system, too. That is not stereotyping. It is looking out for the safety and well being of a person.


I want to know why a practitioner would test a patient for drugs while they're on medicines? I don't understand that or stereotyping people because of its outcome, and also refuse to treat a person because of it. Isn't that stereotyping? I almost died because my doctor said I'm a user of marijuana. I found that kind of amusing at first, because I passed my drug test at work. But at my job, I was allowed a form to fill out that listed everything I take, including over-the-counter meds and homeopathic remedies. I contested my doctor's findings for my character's sake, because he was rude to me, and he was also trying to stereotype me too.

I asked him why he was testing me, and why wasn't I allowed to fill out a form like I do at work. He said he wouldn't look up the over the counter meds I took, because it took him too much time. I think it's wrong to incriminate someone and not even give them a chance to prove otherwise. I was also neglected as far as patient care also, because I had a bad pelvic female infection and I have lupus, and had been in the emergency room for it. They only gave me enough antibiotics to hold me over for three days. I went to my doctor and he only gave me one antibiotic pill and some ointment to put on myself. I ended up back in the emergency room, because I wasn't getting enough antibiotics, and also, he didn't even give me a pelvic exam. How in the hell can he prescribe anything if he didn't do an exam? So I went back again because the ER only gave me enough meds for three days again. That's all they'll do. By the way, since I have an autoimmune disease, it takes a longer course of antibiotics for me to get over infections. What usually kills patients is infections.

Well I went back, he said I'd had enough meds, and still had not examined me, and I was in excruciating pain. It had gone up into my upper abdomen. I finally went back to the ER and begged the doctor there and told him what was going on, and begged him to give me enough antibiotics to get over the infection. He did a pelvic on me and prescribed diflucan for twelve days, plus two more antibiotics. The reason for the other antibiotics is I had been raped and robbed during the Christmas season in a parking lot. That same doctor did not and wouldn't listen to me, because he had poor opinion of me, because of a stupid drug test. I almost died because of this, but he wouldn't hear me out. He did not care. I feel raped again by the medical society.

I want to sue that doctor. I wonder how many other people he has done that to. I've been to appointments on several occasions, and have seen the police in his office and some seriously upset people. I want him investigated too. Is there anyone in here who can help me put the low life in his place?

I'm not a drug user. I have lupus, scleroderma and sjogrens, but I do healthy things. I distance cycle, like Lance Armstrong. I do awareness programs and fund raisers, because I'm a musician, and am in couple of bands. I do this for a cure, if not for me, then the future. I also go to the gym, and I try to be as healthy as I can, my life style is why I have survived this heinous illness so long.

I was a pipe fitter and welder at Exxon before I became ill, and raised three sons on my own. I'm a good person and someone needs to make that doctor atone for what he did to me, and stop him from doing this to others. God bless the ones in here who hurt all the time and suffer from stereotyping and neglect. It's just horrible. -- jojochickrock


Some people who are doing urine testing are making me sick. I am a 53 year old woman who has a severe spinal injury and who also has urine testing done, and the last three times, it has been positive for meth and I certainly do not do illegal drugs.

That urine testing is causing me false positives that are causing me more stress to where I am now losing my hair. For the last twelve years, I have been on more medication than one could count so people who are being falsely accused are having their lives ruined due to urine testing.

Urine testing is not 100 percent accurate and the people who give these tests make mistakes, too. When is this going to stop? They need to quit playing with people's lives. I think people who are giving these tests and the people who are demanding these tests done, should also have to take the test themselves. Maybe this will make people look at these tests more seriously and realize they cannot play with people's lives this way.


I'm glad to see all this trouble over false positives taking place. Hopefully, the vast majority of those falsely testing positive and having consequences for it are those who support legislation that enables busybodies everywhere to control what should be private behavior that has no victims. Enjoy it.


My husband applied for a oil field job. He went in to take his UA today and it came up as positive for THC, which he hasn't used. The only thing I can think of that he's taken in the last week or so is ibuprofen and he drinks these weird venom energy drinks. Is it possible either of these can cause this, and if so, when they get the test back from the lab, would it show that it could be either of these factors?


I was fired under Severe Misconduct cause doctor said I smoked marijuana and they found THC on my urine test, but the twist is that I don't do drug. However I take hemp protein and hemp milk and that week I had a cold and took some cold/flu medication. Could it been the result?


my husband took a drug test today is showed up positive for bzo.

he has never used anything that has bzo. is there anything that can make that a false reading?


I don't understand. I had three drug screens with three different employers in a seven day period. Tested positive for weed on one and neg on two.

I don't do drugs at all, and never have. It just doesn't make sense. How could I get exposed and not know it?

I heard advil could give a false positive, and I do have headaches a lot, and take advil 3-4x/day. I don't know; it's weird.


I'm in pain management for chronic pain. I have been trying to eat healthy and taking several different herbs every day. I also take the body cleanse. I do a urine each time i go to ds.

I received a letter three days before my next appointment that my doctor was dropping me due to showing low levels of my meds. They also told me it showed taking other meds. I have not taken anything other than my meds and doing the right things for myself. What herbs are throwing my tests off? I'm now hanging without my meds with no doctor. I have been under a doctor's care for 11 years. I need answers!


How is it that my daughter tested positive for suboxone on a swab test when she has never taken it? it is being sent out for a breakdown now, but the waiting is very stressful.


I recently got out of federal prison for mail fraud and they (the Feds) drug test us daily and PBT as well. I was told B Vitamins and an abundance of other "natural" amino acids cause "false" positives and to stay away from them while on probation. What, am I supposed to not eat healthy after eating absolute garbage for the last two years in prison? Idiots!


I have done a lot of research on hair follicle tests recently because my husband and I are in a custody battle. The hair follicle test is a two step process for those who test positive it actually matches the drug you test positive for by chemical make up sort of like a DNA sample.

If you test positive and you are absolutely sure you are not using, get one heck of an attorney and fight it, but word of caution: these tests are known for hardly ever having a false positive. They are used for their accuracy.


I tested positive for marijuana in spite of no medications, vitamins, or drug use. The only thing I can think of causing it is having come from work with solvents on my hands (WD-40/liquid wrench/gasoline). I had beef BBQ for lunch with baked beans.

I am livid as the test was required for a second job. It is outrageous to me that these tests are treated as gospel when the people doing them are not medical professionals and can't give insight. Any thoughts?


I'm an aircraft mechanic. I was taking hemp seed protein shakes and hemp seed oil caps and I tested positive for thc. Can hemp seed cause you to come out positive on a drug test and is there's a way they could find the difference between them two?


I recently failed a drug test for work. It says I had THC in my system. Knowing I don't smoke, I went on an investigative hunt, only to learn that several things I take, such as B2 B complex and niacin all contain riboflavin and that's made of hemp seed oils, so now i can't take vitamins. And I drink several monster energy drinks every day that also contain B2. Are there any vitamins that don't contain riboflavin that will keep my energy level up?


does anyone know what natural herbs can show up in a drug test. please be specific.


I noticed that it said amoxicillin and penicillin can cause a false negative. would zithromax/azithromycin have the same effect?


How can riboflavin cause a false positive? The only way I could be assured of not having a false positive is if I just stop eating altogether. Everything I eat has this vitamin in it. It can't be avoided.


As a hiring manager, I just tested a 63 year old male, who failed a five panel drug test for meth. Interestingly enough, he and I are on the same drug regime for Type 2. It took three hours for the test to register as a negative. Tried the same drug test. Yep! I failed as well. Mine took 15 minutes to show negative. So if you fail, ask them for a repeat and a three-hour time frame for it to show -- or get a good attorney.

Note: It seems to happen in a greater proportion of hypoglycemics, so get a C-Pat test and check out your insulin levels.


I'm a flight attendant, and was a social drinker. I stopped drinking one year ago. I am fighting a custody battle, and I have been taking FAEE hair testing for a year and they've not returned with the same level. It is between 0.36-0.67. Again, I don't consume alcohol, no drugs, and I get plenty of exercise and take vitamins. What causes the ethanol to rise? desperate.


I am 45 yrs old and now have tested positive for meth. I have never been around anyone who has done meth and have never done it myself.

I have done a hair follicle test but was never asked about any over the counter meds that i have been taking. will they find the Nyquil and Naproxen without being told?


I have taken eight drug tests and they come back for oxycodone. what foods or over the counter medicines can cause a false test for oxycodone?


The Arby's sandwich did it to me too. maybe something in the cow feed.


I need to know if high levels of Tramadol can give a positive result for PCP?


I have recently voluntarily take a drug test by having hair taken and it has come back positive for cannabis.

The doctor said the amount was consistent with being in the presence of someone who smoked it within the last three months.

I do not smoke it and I know nobody who does.

I am absolutely devastated .


I had an Arby's beef and cheddar sandwich and I was positive for THC?


Is it true that hot dogs and bologna can make you test positive for Methamphetamines?


riboflavin is in a lot of foods. how much would need to be digested for a test to come back false positive?


I know someone who takes random drug tests and they are currently taking herbs such as Astragalus with three different kinds of mushrooms: Reishi Maitake and Turkey Tail,and Zhu Ling.

Too they are using Ivy Leaf cough syrup and L-theanine for concentration. Would any of these show on a drug test? Thanks.


If you take 100 mg of benadryl 4 times a day for 3-4 days can it cause you to show a false positive on a drug test?


I am on vicodin, somam, ibuprofen, HTCZ, lexapro, ambien and was on antibiotics at the time of my drug test. I also take over the counter antihistamines, benadryl and sudafed due to allergies, and I have chronic bronchitis. I do not take illegal drugs of any kind, however. In the past two years I have had two positive results for meth. Why is this coming up positive?


There are several different types of tests in use around the world, and it is true that some of the most recent testing methods can account for the presence of chemicals released in the body by poppy seeds. However, unless you know for sure the testing method employed will omit a false positive reading on poppy seeds, it is a good idea to go ahead and make it known you had a poppy seed bagel recently or enjoyed poppy seed dressing on a salad last night.


I had heard that the tests were advanced enough that poppy seeds didn't actually show up - is this not actually true?

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    • Poppy seeds can skew drug testing results by showing up as an opiate.
      By: photocrew
      Poppy seeds can skew drug testing results by showing up as an opiate.
    • Many employers conduct random drug testing on their employees.
      By: Wojciech Sobiech
      Many employers conduct random drug testing on their employees.
    • Amoxicillin can cause problems on a drug test.
      By: Oleksii Nykonchuk
      Amoxicillin can cause problems on a drug test.
    • Some prescription drugs can show up on a drug test because their ingredients are sometimes similar to those of illegal drugs.
      By: candy1812
      Some prescription drugs can show up on a drug test because their ingredients are sometimes similar to those of illegal drugs.
    • When preparing for a drug test, individuals may want to provide the testing facility with a list of medications, vitamins and herbal supplements taken recently.
      By: Rob Byron
      When preparing for a drug test, individuals may want to provide the testing facility with a list of medications, vitamins and herbal supplements taken recently.