Marijuana and Alcohol
Drinking and cannabis together is not just two buzzes at once: alcohol raises THC levels and the pair worsens driving more than either alone.
Battling addiction & ready for help?
What Happens When You Mix Marijuana and Alcohol?
Mixing the two and feeling sick or unsafe? Greening out, a bad reaction, or a heavy night — here's what to do right now.
- Greening out (nausea, dizziness, racing heart): sit or lie down somewhere cool, sip water, and ride it out — it passes. Do not drive.
- Stop adding alcohol. Drinking more is what turns a rough buzz into a dangerous one.
- Never drive, and don’t let a friend drive. The combination wrecks coordination more than either alone.
- If drinking has its hooks in you, detox with medical support is the safe, easier way out. Call SAMHSA at 1-800-662-HELP (4357), free and confidential, 24/7.
Drinking and using cannabis at the same time isn’t two mild buzzes side by side. Alcohol raises the amount of THC that reaches your blood, so the cannabis hits harder than it would on its own. That’s the mechanism behind “greening out”: the spinning room, the nausea, the cold sweat that follow when people drink first and then smoke.
Using both together is common, especially among young adults, and most of the time it doesn’t end in an emergency. The risks worth knowing are quieter. People tend to drink more when cannabis is in the mix, the two impair driving more than either alone, and the combination is genuinely dangerous during pregnancy.
- Alcohol boosts THC. Drinking raises the peak THC level in your blood, so the same cannabis hits harder and “greening out” (nausea, dizziness, a racing heart) gets more likely.
- People drink more when both are in the mix. Combining the two also impairs driving more than either substance alone.
- It’s genuinely dangerous in pregnancy. Combined exposure can worsen harm to a developing baby beyond alcohol on its own.
How Marijuana and Alcohol Interact in Your Body
Researchers call it “simultaneous alcohol and marijuana” use, or SAM, and it behaves differently from using either substance on its own.
Alcohol Raises Your THC Level
The key interaction is pharmacological. A meta-analysis of controlled trials found that alcohol significantly increases the peak blood concentration of THC, the active compound in cannabis, and rated the evidence high-certainty[1]. In plain terms, the same amount of cannabis hits harder when you’ve been drinking.
Why People Green Out
That THC spike is what tips a pleasant buzz into feeling sick. When alcohol pushes THC higher than expected, people get dizziness, nausea, sweating, and a racing heart — the cluster casually called greening out. Drinking first and then using cannabis is the order most likely to trigger it.
It Nudges You to Drink More
SAM use is widespread among young adults, and it changes drinking behavior[2]. On occasions when people use both, they tend to drink more heavily than on alcohol-only occasions, and they report more substance-related problems[3]. Social settings and the wish to enhance a good time are the usual triggers for reaching for both[3].
The Real Risks of Weed and Alcohol Together
Most SAM use passes without incident, so it’s worth being precise about where the genuine dangers sit.
Three stand out:
- A rougher, less predictable high. Because alcohol raises THC levels, the combined effect is harder to predict than either drug alone, which is how people end up more impaired or more nauseated than they planned[4]. The unpredictability, not some unique poison, is the everyday risk.
- Heavier drinking and its fallout. If cannabis reliably leads you to drink more, you carry all of alcohol’s downstream risks with it, from binge drinking to the next-day toll. For some people that nudge is the difference between a couple of drinks and a heavy night.
- Sharply worse driving. A level of each you might rationalize separately becomes a serious hazard behind the wheel when combined (more on that below).
Order matters. Drink first, then use cannabis, and alcohol drives more THC into your blood, so the cannabis hits harder and “greening out” gets more likely. Use cannabis first and it can blunt the nausea that would otherwise make you stop drinking, so you drink more. Either sequence stacks the deck, just in a different way.
Marijuana, Alcohol, and Driving
This is where the combination turns clearly dangerous, and the evidence is strong.
Each One Impairs Driving on Its Own
Cannabis roughly doubles the risk of a motor-vehicle crash, with impairment that climbs as blood THC rises[5]. Drivers tend to slow down to compensate, but control still breaks down as the task gets harder — lane weaving, slower reactions, divided attention.
Together, It’s Worse
Combining cannabis with alcohol enhances driving impairment beyond either substance alone, especially lane weaving[5]. The takeaway is simple: amounts you could rationalize separately add up to a serious hazard behind the wheel.
Marijuana and Alcohol During Pregnancy
One context flips this from “use caution” to “do not.” Alcohol is among the most harmful substances to a developing baby, and between 1% and 7% of children show signs of fetal alcohol spectrum disorder[6].
Cannabis frequently accompanies alcohol use, and the combined developmental exposure can be synergistic, worsening the damage beyond alcohol alone[6]. There is no known safe amount of either during pregnancy, and together the risk compounds.
How the Effects of Marijuana and Alcohol Stack Up
| Effect | What’s happening |
|---|---|
| Higher THC | Alcohol raises peak blood THC, so cannabis hits harder |
| Greening out | That spike brings nausea, dizziness, and a racing heart |
| More drinking | People drink more on occasions when they also use cannabis |
| Impaired driving | The combination worsens driving more than either alone |
| Pregnancy harm | Combined exposure can synergistically worsen developmental damage |
When the Drinking Is the Part That’s Grown
If drinking has crept up, with cannabis in the picture or not, treatment helps, and there’s no need to wait for things to fall apart. A provider who treats alcohol and other substance use together is the most useful first step.
If you drink heavily every day, stopping abruptly can be dangerous on its own — which is exactly why a supervised detox is the safe, easier way to do it, with medication to ease the worst of it. The way out is far gentler than the agony most people picture.
The next step doesn’t have to be a big one. If you drink heavily, talk to a doctor before stopping — withdrawal can be dangerous. For free, confidential help 24/7, call SAMHSA’s National Helpline at 1-800-662-4357, or our treatment centers directory can point you to the right level of care, from outpatient to medically supervised detox. Reaching out today is a real step forward.
Frequently asked questions
What happens when you mix marijuana and alcohol?
Alcohol raises the peak level of THC that reaches your blood, so the cannabis feels stronger than it would alone[1]. That spike is behind ‘greening out’, the nausea, dizziness, and racing heart that can follow. People also tend to drink more on occasions when they use both, and report more substance-related problems[3].
Why does mixing weed and alcohol make you sick?
Because drinking pushes your THC level higher than the cannabis alone would[1]. When THC spikes past what your body expects, you get the dizziness, nausea, sweating, and rapid heartbeat people call greening out. Drinking first and then using cannabis is the order most likely to trigger it.
Is it more dangerous to drink and use cannabis at the same time?
The combined effect is harder to predict, which is the everyday risk[4]. People also drink more heavily when cannabis is involved, carrying all of alcohol’s downstream risks with it[3]. The clearest danger is driving: combining the two impairs driving more than either substance alone[5].
Is it safe to drive after using marijuana and alcohol?
No. Cannabis alone roughly doubles crash risk, and impairment increases as blood THC rises[5]. Combining cannabis with alcohol enhances driving impairment beyond either one alone, especially lane weaving[5]. A level of each you might rationalize separately becomes a serious hazard behind the wheel together.
Can you use marijuana and alcohol while pregnant?
No. There is no known safe amount of alcohol during pregnancy, and between 1% and 7% of children show signs of fetal alcohol spectrum disorder[6]. Cannabis often accompanies drinking, and the combined developmental exposure can be synergistic, worsening the harm beyond alcohol alone[6].
How common is using marijuana and alcohol together?
Common, especially among young adults aged 18 to 30, where simultaneous use is widespread[2]. Social settings and the desire to enhance a good time are the usual triggers for using both at once[3]. Most use passes without an emergency, but it reliably shifts drinking upward and makes the combined high less predictable.
Get Treatment Help
If you or someone you love is struggling with addiction, getting help is just a phone call away, or consider trying therapy online with BetterHelp.
Exclusive offer: 20% Off BetterHelp*Following links to the BetterHelp website may earn us a commission that helps us manage and maintain AddictionHelp.com. *Get 20% off your first month of BetterHelp. Offer valid for new BetterHelp users only. Offer cannot be combined with insurance.
- Fact-Checked
- Editor
