If you’re looking for ways to avoid a positive drug test, you’ve probably come across advice suggesting that you drink vinegar to “clean” your system in a single day. What’s the deal?

Some people claim apple cider vinegar (ACV) has certain detoxifying properties that help it clear out “toxins” — including THC, the cannabis compound that drug tests detect — from your body in 24 hours. But does it actually work? And is it even safe to try?

Here’s a look at the science behind it.

The claims around why vinegar supposedly cleans your system are vague. But the way your body metabolizes cannabis offers some clues.

When you ingest cannabis, the THC is quickly broken down into an inactive metabolite. This metabolite joins with glucuronic acid to create an acidic metabolite that’s excreted in your urine.

Some say that the acidic environment created by drinking vinegar allows more THC to be excreted this way in less time, but there’s no evidence to back this up.

Others suggest adding some ACV to your urine sample to lower the pH, potentially resulting in a false negative result.

Again, there’s no evidence to suggest that drinking vinegar will help your body to quickly cleanse itself of THC. Even if it were to somehow work, your urine sample would likely raise some eyebrows.

Most ACV “cleanses” designed to help you avoid a positive result instruct you to consume at least a gallon of water in the hours leading up to the test. This results in noticeably diluted urine. In some cases, providing diluted urine could cause you to automatically fail the test. In others, you’ll be asked to provide another sample, often under supervision.

As for adding ACV to your urine sample, this is also likely to raise a red flag. Drug-testing facilities are quite familiar with this method and test the pH levels of samples to ensure that they’re within a normal range. The typical pH of a valid urine sample ranges from 4.5 to 8.0, while the pH of apple cider vinegar is usually around 2.0 to 3.0.

Keep in mind that samples are typically also tested for:

Vinegar isn’t a reliable way to “clean” your system. But is there any physical harm in trying it anyway?

Not really. ACV is pretty safe, but it is quite acidic. If you decide to try this method, make sure that you dilute it with water before drinking it. Also be sure to rinse your mouth with plenty of water afterward to protect your teeth.

Despite all the products that promise to do so, there’s no reliable way to quickly rid your body of a substance. To avoid a positive result, you’ll need to wait for your body to process things on its own timeline.

This timeline varies from person to person depending on a range of factors, including your body composition and how long you’ve been ingesting the substance.

When it comes to cannabis, you’re looking at anywhere from 1 to 30 days.

Here’s how long other common substances are detectable in urine samples:

  • amphetamines: 2–4 days
  • barbiturates: up to 7 days
  • benzodiazepines: up to 7 days
  • cocaine: 1–4 days
  • codeine: 2–4 days
  • heroin: 2–3 days

There’s no evidence that vinegar “cleans” your system. Even if it did, your urine sample likely wouldn’t be accepted.

If you’re concerned about an upcoming test, your best bet is to simply let your body work things out naturally.

Adam England is a freelance writer and journalist. His work has appeared in publications including The Guardian, Euronews, and VICE UK. He focuses on health, culture, and lifestyle. When he’s not writing, he’s probably listening to music.