Does aspirin work to pass a drug test?

Does taking aspirin help pass a drug test?

On social media, numerous people state that aspirin helped them pass a piss test. Let’s explore and analyze their comments below:

This forum user describes taking 4 aspirin and drinking a cup of water along with it on an empty stomach to beat marijuana lab tests. In about a half-hour after smoking, he has managed to pass a drug test using a testing kit bought online. He also passed another test about another half an hour later. This suggests aspirin goes to work fast and helped him pass a urine cannabis test for as long as an hour. Other sources say the effect can last up to 5 hours.

Negative Review (aspirin 4 urine drug test)

This user on the forums failed on his first try but has passed using the method before. However, he seems to have a goal of taking 8 aspirin in 2 hours. This is may not be safe. Aspirin in such volume may cause damage to your stomach and make your blood unable to clot. It is not a medication to take lightly. You shouldn’t take more than 500 mg every 4 hours without a doctor’s orders, and no more than 4 grams per day. However, it could take as much as 34 grams of aspirin to be a deadly amount. The greater danger is damage to your stomach and symptoms of the blood being unable to clot, leading to unstopped bleeding.

This has jogged our thinking. Let’s examine what aspirin is, what are the dangers, does aspirin show up on a drug test, and if it, in fact, helps with passing urine drug screens.

What is aspirin?

Aspirin is medically known as acetylsalicylic acid. It is used as a pain reliever, blood thinner, and fever reducer. OTC aspirin is commonly used for headaches. It works by affecting several factors in the immune system resulting in a decrease in an inflammatory response.

Negative Side Effects and Health Risks

The greatest danger using normal doses of aspirin is stomach bleeding. It can cause painful ulcers in the stomach and aggravate any gastrointestinal bleeding such as from hemorrhoids.
The second greatest threat is bleeding in other areas of the body from injury. You could lose a lot of blood from what would have been a minor injury, or old injuries could begin bleeding, externally or internally.
Reye’s syndrome is a rare disorder associated with aspirin, mostly in children recovering from infections. To be on the safe side, do not attempt this method if recovering from flu or infection. Vomiting is an early symptom and it can progress to brain damage and death.

How do people use aspirin to pass a drug test?

From our research, the explanation for the use of aspirin as an adulterant is that cheaper drug tests, called EMIT or Enzyme multiplied immunoassay technique, is susceptible to producing false negatives when interacting with urine containing aspirin. This has been known scientifically at least since 1994 (Wagener, Linder, and Valdes). The given study found that adding aspirin directly to the urine specimen did not lead to a decrease in accuracy; however, ingesting a therapeutic dose of aspirin worked well. There was a positive dose-response found. The higher the dose, the greater the reduction in the ability to detect drug use. Do not, however, be tempted to take large doses of aspirin as this is not safe.


  1. People who use this method take four or five 325 mg aspirin with a glass of water.
  2. Some people combine this method with dilution. Others say dilution will ruin the effect. We will assume here that you should not use dilution with this method. It does not work via dilution. It works because aspirin interferes with the test results.

Evidence suggests that this approach will work with cheaper EMIT tests, but may not work for more expensive, more sophisticated tests. Some testing techniques can also uncover the use of aspirin. Your sample could be disqualified. You may fail or be required to retest.

Can you use Robaxisal? Does methocarbamol have aspirin in it?

Robaxisal is a combination of methocarbamol and aspirin. Methocarbamol is a muscle relaxant which is not a narcotic. Therefore, it will not be tested for in most drug tests. It is still better not to worsen things by using a combination product. Get cheap, generic, coated aspirin instead.

Social Media Reviews

Positive Review: “I PASSED!”

This Reddit user used several grams of aspirin. Again, this does not appear like a safe thing to do. Do not use more aspirin than recommended on the bottle and do not exceed the highest OTC doses which are 4 grams or 4000 milligrams. The studies on aspirin do not appear to have used mega doses to induce false negatives in EMIT tests, so don’t end up in the ER. Drug tests are serious but not that serious. Just use regular doses.

Negative Review. “…aspirin no longer can beat the test.”

Green crack is a potent strain of marijuana. This Reddit user appears to smoke regularly. We selected this review because he points out something that we have suspected, that aspirin, though effective in the past, may now be largely detectable by more sophisticated drug tests. As suggested by the reviewer, a dilution method is usually the way to go. Dilution can also be done via a trusted detox drink.

Conclusion: Can aspirin help pass a drug test?

Aspirin, in the past, has been known scientifically to be able to produce false-negative drug test results, specifically for enzyme multiplied immunoassay technique (EMIT) tests. These tests are often still used in practice for routine drug tests. So, this is an iffy proposition. There are more sure-fire ways to pass a drug test, including detox drinks, substitution, synthetic urine, and dilution. Also, be careful that you do not experience the side effects associated with aspirin abuse, such as stomach ulcers and bleeding.

If you opt to use aspirin, the technique used by the more reasonable experimenters suggest taking four aspirin with a glass of water, and test at least 30 minutes afterward but within a five-hour window. You should urinate three times before your test. When you test, you wanna catch your midstream pee. To urinate in the toilet for a bit, then into the sample cup, then finish in the toilet. You need to collect 3 to 5 ounces of urine. The aspirin or aspirin metabolites will interfere with the ability of EMIT tests to measure levels of nearly every drug class studied. As a result, the tests will show reduced or undetectable levels of drug traces including THC-COOH, the metabolite of THC that discloses the use of psychoactive marijuana products. If you get in a bind and have fewer options and little time, popping a few aspirins about an hour before your test might give you just the edge you need to pass. Good luck and be safe!


Wagener, R E, M W Linder, and R Valdes. “Decreased signal in Emit assays of drugs of abuse in urine after ingestion of aspirin: potential for false-negative results.” Clinical Chemistry 40.4 (1994): 608-612. 4 3 2019.

This article about Medical Marijuana was published on and updated on October 27, 2022 . Medical facts in this article was checked and article was medically reviewed by our . Author of this checked article is
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