What Happens When I Mix Marijuana and Alcohol: Side Effects, Interactions & Risks

Last Updated: February 1, 2024

Editorial Policy | Research Policy

Mixing alcohol and marijuana can lead to a variety of dangerous risks, including higher levels of THC and alcohol poisoning.

Marijuana is one of the most commonly used drugs among drinkers1, second only to tobacco. Also known as “crossfading,” mixing marijuana and alcohol can enhance the effects of each drug and lead to a number of dangerous health risks. . People who mix alcohol and marijuana may also take more than intended, as increased use of one substance tends to cause increased use of the other.

What Happens When They Mix

Mixing alcohol and weed can alter the effects each substance would have on its own, leading to uncomfortable or even dangerous situations. Further, factors like a person’s drug and alcohol tolerance, metabolism and medication use can influence the effects as well.

Each substance can also influence the effects of the other. For example, alcohol can cause higher levels of tetrahydrocannabinol (THC)6, the active ingredient of marijuana, to be absorbed by the body. Elevated THC levels tend to occur when alcohol is consumed before using marijuana.

When weed is used before alcohol, research suggests it inhibits the effects of alcohol1. This can create a situation where someone accidentally uses too much alcohol or develops alcohol poisoning. This effect can also prevent someone from realizing how impaired they are, leading them to take risks they otherwise would not.

Other FAQs

What happens if I smoke weed before drinking?

Available research indicates that weed inhibits the effects of alcohol3. This means someone who uses weed before drinking may have to consume more alcohol to get the same effect, increasing the risk of an alcohol overdose.

What happens if I drink before I smoke weed?

Drinking prior to using weed increases how much THC is absorbed6 from the weed, making its effects much stronger. While this may result in a more intense high for some, it can also cause someone to “green out.”

What is greening out?

“Greening out” is a slang term that refers to the unpleasant effects that occur when someone overdoses on weed4. While overdosing on weed is unlikely to be dangerous, it can cause many distressing, unpleasant symptoms. These include:









These symptoms are temporary, but it may take hours for them to pass.

Overdose Risk

Mixing alcohol and marijuana increases the risk of overdosing on either substance. Marijuana overdose is more likely because alcohol makes more THC be absorbed. Alcohol overdose is more likely because marijuana impairs the perception of how much alcohol has been used, leading to overuse.

Marijuana overdose, or “greening out,” can be a very unpleasant experience but is not considered to be dangerous. Alcohol overdose is far more serious and can cause a variety of health risks, some of which can be fatal.

Recognizing Alcohol Poisoning

Being able to recognize when someone has overdosed on alcohol can play an important role in saving their life. According to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), signs of alcohol poisoning5 include:

  • Mental confusion
  • Difficulty remaining conscious
  • Vomiting
  • Seizures
  • Trouble breathing
  • Slow heart rate
  • Clammy skin
  • Dulled responses
  • No gag reflex
  • Extremely low body temperature

If someone you are with has been drinking and begins to develop these symptoms, you should immediately call 911 (in the USA) and stay with them until medical help arrives. Alcohol poisoning can cause permanent brain damage or death.

Other Risks To Consider

While the risk of overdose when mixing alcohol and marijuana is definitely a consideration, there are other potential problems that can occur.

Dependence occurs when the body develops a need for a substance to be present to function normally. The development of dependence is related to the length of time a substance is used as well as the dose taken. When you mix alcohol and marijuana, the dose of each could be artificially elevated, increasing the risk of dependence.

Mixing alcohol and marijuana can impair your cognitive function beyond a simple additive effect. Combined with the decreased inhibition that alcohol causes, this can significantly increase the risk of accidental injuries and lead to physical risks that would not otherwise have occurred.

Because marijuana can inhibit alcohol’s effects, it may lead someone to underestimate how much alcohol they have used. While this can increase the risk of overdose, it can also cause someone to drive over the legal limit without realizing it. This increases the risk of accidents and the risk of legal problems.

Is It Safe?

There are significant risks associated with mixing alcohol and marijuana. While someone may mix them for a while without having any negative effects, each time they do, they increase the risks they expose themselves to.

Mixing substances like alcohol and marijuana together may indicate an addiction. It can be difficult to stop using drugs and alcohol, but when mixing these substances is creating a potential safety risk, it is time to stop using them.

If you or someone you know is struggling with marijuana, alcohol or any other substance, The Recovery Village Cherry Hill at Cooper is here to help. Contact us today to speak with a knowledgeable representative and learn more about treatment programs and resources that can work well for you.


  1. Subbaraman, Meenakshi S; Kerr, William C. “Simultaneous vs. concurrent use of alcoh[…]ional Alcohol Survey.” Alcoholism: Clinical and Experimental Research, May 2015. Accessed November 26, 2021.
  2. Hartman, Rebecca L.; Brown, Timothy L.; et al. “Controlled Cannabis Vaporizer Administra[…] and without Alcohol.” Clinical Chemistry, June 2015. Accessed November 26, 2021.
  3. Lukas, S.E., Benedikt, R., et al. “Marihuana attenuates the rise in plasma […]ls in human subjects.” Neuropsychopharmacology, August 1992. Accessed November 26, 2021.
  4. Murphy, Kathryn. “Greening out” Treating cannabis-related problems in the ED.” Wolters Kluwer Health, November 2017. Accessed November 26, 2021.
  5. National Institute on Alcohol Abuse and Alcoholism. “Understanding the Dangers of Alcohol Overdose.” May 2021. Accessed November 26, 2021.
  6. American Association for Clinical Chemistry (AACC). “Any dose of alcohol combined with cannab[…]els of THC in blood.” ScienceDaily, 27 May 2015. Accessed October 25, 2022.

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