What happens when you mix alcohol and weed?

Article written by

Dr. June ChinChief Medical Officer
Alcohol and cannabis are two of the most widely used intoxicating substances in the world.
While it’s common to mix the two, doing so may increase the risk of certain side effects, including dizziness and drowsiness.
Understanding the possible risks of using cannabis and alcohol together can help you enjoy them safely and responsibly.
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What happens when you mix alcohol and weed?
Alcohol increases the absorption of tetrahydrocannabinol (THC), the main intoxicant in cannabis. This means that consuming both can make you feel more intoxicated or “high.”
Cannabis might also delay the effects you feel from alcohol, leading you to consume more than you normally would.
Alcohol is a sedative that helps the brain release “feel-good” chemicals, such as:
- Dopamine: Increases feelings of pleasure and satisfaction
- Gamma-aminobutyric acid (GABA): Produces a sense of calm
However, alcohol can cause side effects, especially when consumed in high doses, including:
- Dizziness
- Drowsiness
- Nausea and vomiting
- Poor sleep quality
- Slurred speech
- Vision problems
- Poor coordination
- Confusion
Like alcohol, cannabis can promote relaxation and euphoria. The compounds in cannabis act on brain receptors that balance chemicals, including dopamine and GABA.
Cannabis can also cause side effects, such as:
- Dizziness
- Drowsiness
- Nausea and vomiting
- Headache
- Poor coordination
- Fast heartbeat
- Confusion
While alcohol can cause fatal overdose, no deaths have been caused by consuming cannabis alone.
Effects of alcohol and weed combined
Consuming cannabis and alcohol — known as “cross-fading” — can increase side effects associated with both substances, such as:
- Dizziness
- Drowsiness
- Nausea and vomiting
- Poor coordination
- Confusion
Does the order you use them matter?
Drinking alcohol before using cannabis can increase the effects of THC by widening your blood vessels, helping THC absorb into your body. This can make cannabis affect you more quickly than it normally would.
Using cannabis first might delay the effects of alcohol. This could cause you to drink more than you normally would, increasing your risk of negative effects, like alcohol poisoning.
Risks of combining alcohol and weed
While it’s possible to consume alcohol and cannabis together safely, the combination carries both short and long-term risks, especially if one or both are consumed in excess.
Short-term risks
Combining alcohol and weed poses some immediate risks:
- Impaired driving: Compared with people who use alcohol and cannabis separately, people who mix them are about twice as likely to drive under the influence.
- Low impulse control: Mixing alcohol and cannabis can make you more likely to engage in risky or sensation-seeking behaviors, increasing your chance of an accident or injury.
- Greater chance of blacking out: Combining cannabis and alcohol puts you at a greater risk of memory loss and blackouts compared to only drinking alcohol.
- Reduced risk of vomiting: Cannabis may prevent nausea and vomiting, which can interfere with your body trying to get rid of the toxins in alcohol.
- Impaired brain function: Mixing alcohol and cannabis can lead to clumsiness, confusion, dizziness, and difficulty concentrating.
Long-term risks
Frequently using cannabis and alcohol together can cause negative effects over time:
- Long-term brain changes: Chronic use of alcohol and cannabis can cause changes to your brain structure, including your hippocampus, which helps regulate emotions, memory, and learning.
- Increased tolerance: Consuming alcohol and cannabis can lead to increased tolerance and use of both, requiring you to consume more to achieve the same results.
- Dependence: People who mix alcohol and cannabis tend to be more frequent and heavier users of both substances. Dependence can lead to alcohol addiction and marijuana substance abuse.
- Mental health problems: Using both substances can increase your risk of depression and psychosis.
Help is available
If you feel you’ve lost control over your alcohol or cannabis consumption, you’re not alone. Reach out to your healthcare team for support or call 800-662-HELP (4357) to access the Substance Abuse and Mental Health Services (SAMHSA) National Helpline. It’s free, confidential, and available 24/7.
Tips for combining weed and alcohol
If you plan on using alcohol and cannabis together, follow these safety tips:
- Start low and go slow: It’s important to avoid taking too much of either substance, especially because alcohol can increase THC’s effects, and THC can delay the effects of alcohol. Consider taking less of each substance than you normally would when consuming them on their own.
- Monitor how you feel: Pay attention to how you feel, looking out for particularly dangerous side effects like confusion or excessive vomiting. If you are experiencing unusual or severe side effects, seek medical attention.
- Avoid risky activities: Avoid risky activities that may lead to accidents or injuries. Driving while under the influence of either alcohol or cannabis is illegal.
The bottom line: Mixing alcohol and cannabis comes with some risks
While it’s possible to consume cannabis and alcohol together safely, there’s a risk of increased side effects.
In rare cases, this combination can lead to alcohol poisoning, as cannabis can delay the effects of alcohol.
If you have any concerns or questions about combining these substances, a Leafwell provider can give you personal guidance.
Resources
- Alcohol-associated liver disease. https://www.ncbi.nlm.nih.gov/books/NBK546632/
- Alcohol in the body. https://pmc.ncbi.nlm.nih.gov/articles/PMC543875/
- Cannabinoid ligands and alcohol addiction: A promising therapeutic tool or a humbug? https://link.springer.com/article/10.1007/s12640-015-9555-7
- Consequences of alcohol and marijuana use among college students: Prevalence rates and attributions to substance-specific versus simultaneous use. https://pmc.ncbi.nlm.nih.gov/articles/PMC7064425/
- Co-use of alcohol and cannabis: A review. https://link.springer.com/article/10.1007/s40429-017-0149-8
- Drug fact sheet: Marijuana/cannabis. https://www.dea.gov/sites/default/files/2020-06/Marijuana-Cannabis-2020_0.pdf
- Ethanol increases plasma Δ9-tetrahydrocannabinol (THC) levels and subjective effects after marihuana smoking in human volunteers. https://www.researchgate.net/publication/11802477_Ethanol_increases_plasma_D9-tetrahydrocannabinol_THC_levels_and_subjective_effects_after_marihuana_smoking_in_human_volunteers
- Marihuana attenuates the rise in plasma ethanol levels in human subjects. https://pubmed.ncbi.nlm.nih.gov/1326277/
- Risk factors for simultaneous use of alcohol and cannabis. https://www.publichealthontario.ca/-/media/documents/e/2018/eb-risk-factors-alcohol-cannabis.pdf?sc_lang=en
- Simultaneous alcohol and marijuana use in daily life: Implications for level of use, subjective intoxication, and positive and negative consequences. https://pmc.ncbi.nlm.nih.gov/articles/PMC7148190/
- Simultaneous use of alcohol and marijuana: Patterns and individual differences. https://www.tandfonline.com/doi/full/10.1080/10826084.2019.1638407
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Frequently asked questions
Find out more about combining cannabis with alcohol from these FAQ answers.