Does Aspirin Work to Pass a Drug Test

Many users employ various different approaches, methods, and products in an effort to be a drug test. Throughout this article, we will look at whether aspirin can help you beat a test.  There are two popular methods promoted online for using aspirin as part of a weed detoxification regimen.  Undertaking a detox to cheat on a drug test may be undertaken for a test related to employment purposes or in relation to probation or other legal matters.  It is against the law to use a detox effort to beat a drug test in some U.S. states.  So be sure to check what the law says in your region before delving further into the world of detox, whether an aspirin-based detox or otherwise.


What is Aspirin?

Acetylsalicylic acid or Aspirin tends to be used as pain relief medication, as a blood thinner, and as a means to reduce fever.  It’s common for OTC aspirin to be used for headaches.  Aspirin works by affecting different factors in the body’s immune system which leads to a decline in an inflammatory reaction.  In particular, it reduces prostaglandins, an inflammatory molecule the body uses to fight infection, and to get ready for invaders if you have a tear in the skin.  It may help cause swelling and vasodilation.

Aspirin was discovered while willow bark used in ethnomedicine in Europe and elsewhere.[2]  It’s used for pain, Kawasaki disease, headache, rheumatic fever, and as a blood thinner in cardiovascular disease.  It is generally sold over the counter.  Some derivatives are prescription medications.

When You Should and Shouldn’t Use Aspirin for a Urine Drug Test

Do not use if:

You should avoid aspirin as per your doctor’s instruction if:

  1. You have liver disease.[3]
  2. You have kidney disease.  This can cause abnormally high levels and the blood will be unable to clot.
  3. If you have 3 or more alcoholic drinks per day.  It can cause stomach bleeding, and you may also have undiagnosed liver or kidney problems.
  4. If you have malignant hypertension.  Blood vessel tears may be unable to repair due to the inability to clot caused by aspirin.
  5. If you already take another blood thinner.
  6. If you are having a stroke.  It’s hard to tell the difference between heart attack and stroke.  Aspirin may help a heart attack but worsen a stroke by causing uncontrolled brain bleeding.  Let a doctor determine whether you need the aspirin or not.
  7. You have ulcers.
  8. You have glucose-6-phosphate dehydrogenase deficiency.
  9. You have dengue fever.
  10. You have gout.
  11. You have the flu

You can use it if you have no contraindications and you use only doses recommended on the bottle.  We are not recommending using it to pass a drug test, we are merely describing how people use it and more so, the scientific studies which have been conducted.

Negative Side Effects and Health Risks

The main risk associated with taking aspirin in normal, safe doses is that of stomach bleeding.  Even safe doses of aspirin can result in painful stomach ulcers and may aggravate any existing gastrointestinal bleeding including possibly from hemorrhoids.  The second most prominent danger is bleeding in different regions of the body from injury.  It’s possible that you could lose plenty of blood from what would’ve been just a small injury.  Alternatively, old injuries could start to bleed, either internally or externally.  Aspirin is also associated with Reye’s syndrome, which is a rare disorder that mostly occurs in children due to infections.  To keep on the safe side, avoid this method if you are recovering from the flu or infection.  An early symptom of this disorder is vomiting and it may progress to brain damage and death.

Aspirin can interact with:

  • warfarin,
  • phenytoin,
  • other NSAIDs,
  • methotrexate,
  • antidiabetic drugs tolbutamide and chlorpropamide,
  • valproic acid
  • Probenecid.

What methods do people use involving aspirin to beat piss testing for finding marijuana in urine?

A study in 1994 in the Clinical Chemistry journal found that the ingestion of aspirin did indeed cause false negatives in drug tests.  They concluded:

“…Emit d.a.u. assays after salicylate ingestion lead us to conclude that ingestion of therapeutic doses of aspirin may cause false-negative results for drug screens in urines by this technology.”

In 1994 at least, ingestion of normal doses of aspirin could allow you to pass a drug test.  However, testers may have wised up by now.

A follow-up study in 1994 claimed to have found a way to get around false negatives from aspirin.  It is not known if any such technique was actually adopted successfully by drug testing scientists and companies.  [4]

A study in 2018, published in The Annals of Clinical Biochemistry suggested that aspirin might interfere with the detection of marijuana only.  It may not be effective for other drugs.  It also listed many other effective adulterants which were added directly to the sample, sodium nitrate being the most effective for multiple drugs.  Also, oxidizing agents were effective.[5]


  1. Users of aspirin to alter the detection of drugs in urine take 4 or 5 pills of 325mg  aspirin with a glass of water.
  2. Some users also use dilution when they use this method.  Other users say that will ruin the effect by diluting the aspirin.  According to, 4 grams per day is the upper limit of what you can take as far as aspirin.[6]  I would suggest even 5 pills could give you some stomach upset and adverse effects so do your research, don’t take more than the maximum stated on the label of the product which you have.  For this method, you should not be taking 4 grams of aspirin.  That seems like too much.  Read the label, follow their instructions.


Q:  What does Aspirin due to THC?
A:  Most likely it just interferes with emitting tests such that THC is less detectable.  It’s possible it somehow helps break down THC.  The ability to break up fat could somehow help destroy THC which is fat-soluble.

Q:  Does aspirin show up on a drug test?
A:  As far as we know, it does not.  Though scientists are able to detect it, this ability may not be practiced in testing labs.

Q:  Does methocarbamol have aspirin in it?
A:  Methocarbamol is a guaifenesin derivative which is used as a muscle relaxant.  It is sometimes combined with aspirin as in the product Robaxisal.

Pros and Cons of using aspirin tablets for weed detoxing

Pros Cons
  1. May defeat older Emit tests.
  2. You only need to take only normal doses.
  3. May destroy THC by breaking up fat.
  4. Scientifically known to beat drug tests since the 1970s.
  1. May not defeat new, more sophisticated tests.
  2. Overdose can cause severe side effects.
  3. It can cause stomach upset or bleeding.
  4. Aggravates ulcers.  Drug users are more likely to have ulcers.

Reviews from social media

Does taking aspirin help pass a drug test?

Yes. Positive

Yes. Positive.

Positive, but 8 years old.  Tests have advanced.  Also, he also used dilution.

4 aspirin failed, however, the line was faint and could read clean in a few days.
Yes.  Passed

Overall, we actually found a few reviews as this is an old method for passing a drug test.  For the record, aspirin is scientifically proven to help beat a drug test, but you may need to use dilution as well to boost the effect.  Aspirin alone can give you a faint line that a tester can decide is negative or positive depending on their stereotype of you.[9]

Conclusion: Can aspirin help pass a drug test?

Yes, this is scientifically proven to help beat older EMIT tests.  However, taking too much or if you have a pre-existing condition can cause serious problems mostly concerning internal or external bleeding due to blood being unable to clot.  Dilution is the most tried and true, and safer method.  Also, taking zinc and papain are safer and will also decrease the reliability of drug tests.[10][11]  There are also commercial adulterants to be added directly to the sample which are proven and cannot yet be detected.[12]  So, use it at your own risk.  For the most part, taking a normal dose of aspirin is safe for most people and you are likely to have it at home already.  Good luck.


[1] “Should I Take an Aspirin Every Day? – MyHeart.” 9 Dec. 2013, Accessed 17 May. 2020.

[2] “Aspirin – Wikipedia.” Accessed 17 May. 2020.

[3] “Who should – and who shouldn’t – take daily aspirin | UC Davis ….” 20 May. 2016, Accessed 17 May. 2020.

[4] “Mechanism and elimination of aspirin-induced interference in ….” Accessed 17 May. 2020.

[5] “False-negative results in the immunoassay analysis of drugs ….” 20 Sep. 2017, Accessed 17 May. 2020.

[6] “Can You Die from an Aspirin Overdose? Plus, Symptoms, and ….” 29 Oct. 2018, Accessed 17 May. 2020.

[7] “My drug test story or how I learned to love the aspirin. – Reddit.” Accessed 17 May. 2020.

[8] “PASSED – Aspirin dilution and “Tampering” Drug test ….” 20 Oct. 2009, Accessed 17 May. 2020.

[9] “Decreased signal in Emit assays of drugs of abuse in … – NCBI.” Accessed 17 May. 2020.

[10] “Papain Adulteration in 11-nor-Ag-Tetrahydrocannabinol- 9 ….” Accessed 17 May. 2020.

[11] “Zinc reduces the detection of cocaine, methamphetamine, and ….” Accessed 17 May. 2020.

[12] “Adulterants in Urine Drug Testing. – NCBI.” 11 Jun. 2016, Accessed 17 May. 2020.


  • Dr. Joseph Koyner

    Dr. Joseph Koyner is a practitioner MD. He specializes in Addiction Medicine. He is an alumnus of UCCS. Koyner is working as a medical consultant for 15 years. Currently, Dr. Joseph is working as a self-employed specialist in Los Altos, California.