Article updated: 2022 Apr 15 / Author Leslie Griver, Robert Henry

How to pass a drug test with Aspirin

Aspirin can help you to pass a urine drug test for marijuana. A scientific study shows that Aspirin can cause false negatives in immunoassay drug tests.

Well, tell you how exactly it works and how to use it.


Take 2*325mg aspirin tablets 4 hours before the test.

aspirin bayer

Taking Aspirin will significantly increase your chances to pass the test if you follow the following flushing method

If you want to know how does this method work, we have already explained it in this article:

How does Aspirin help to pass a drug test

There was a study with 100 urine specimens tested. That study showed that urine with aspirin metabolites had a false negative on immunoassay drug tests.

Although direct addition of Aspirin to urine specimens did not produce the same results.

This study confirms that taking Aspirin several hours before the test can cause a false negative. But you must remember that the results are not guaranteed!

You can increase your chances by taking Aspirin, but it’s essential to do other steps. By doing this, you’ll maximize your chances.


Here are several reviews from Reddit:

“I read that taking a large amount of Aspirin can also mask a positive result. I began drinking 1 liter of water 6 hours before the test and took two multivitamins for color and two 500mg aspirin. 4 hours before I drank yet another liter and pounded another 4 aspirin and a multivitamin. At this point I was urinating about every 20 minutes. Come test time I kept a level head, drank a glass before I left and took the plunge.

I am proud to say I PASSED! Just received my confirmation application and I should be starting next week! I hope this is informative for anyone else who may need to pass a test in the near future.”

“I was a frequent smoker at the time, and although I didn’t smoke for 3 weeks before the test, when I tested myself the day before, I came up positive (shitty metabolism for the fail).

Besides the heavy water-drinking regimen I had been on already for a couple of weeks at this point, the day of the test I took a detox drink, 2 aspirins (to thin my blood so anything being filtered out of it and going into my urine would also be diluted), and some niacin (even though there was already some in the drink) to make sure my pee would be properly pigmented.

And guess what? I passed =]”

Health risks of Aspirin

Please remember that you need to consult your physician before taking any medications.

Common side effects of Aspirin include:

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