Mixing cannabis
and alcohol

Polydrug use is using more than one drug at the same time. People use drugs in combination to either increase their intoxication, or to increase the effect of the first drug taken.

Sometimes people mix two drugs because they are already intoxicated and are no longer making rational decisions about their drug-taking and the wellbeing of themselves and those around them. The more drugs being used at the same time, the more likely it becomes that things will go wrong.

Not counting tobacco, the most common form of polydrug use is alcohol and cannabis. When people mix cannabis and alcohol together at one time, the results can be unpredictable. The effects of either drug may be more powerful, or the combination may produce different and unpredictable reactions.

What are the effects of mixing cannabis and alcohol?

When people smoke cannabis and drink alcohol at the same time they can experience nausea and/or vomiting, or they can react with panic, anxiety or paranoia. Mixing cannabis with alcohol can increase the risk of vulnerable people experiencing psychotic symptoms.

There is some evidence to support that having alcohol in your blood causes a faster absorption of THC (the active ingredient in cannabis that causes intoxication). This can lead to the cannabis having a much stronger effect than it would normally have and can result in greening out .

Greening out is a term commonly referred to in a situation where people feel sick after smoking cannabis. They can go pale and sweaty, feel dizzy, nauseous and may even start vomiting. They usually feel they have to lie down straight away.

It appears that this is more likely to happen if a person has been drinking alcohol before smoking cannabis rather than the other way around.

What are the risks of mixing cannabis and alcohol?

  • unpredictable effects if cannabis and alcohol are used at the same time there is a greater likelihood of negative side effects occurring either physically (greening out) or psychologically (panic, anxiety and paranoia).
  • effects on driving the negative effect that alcohol has on driving is well documented. Cannabis use also affects a person's ability to concentrate and react in driving situations. Even at low doses the combination of alcohol and cannabis is dangerous and places the drivers, their passengers and others on the road at serious risk.
  • getting too intoxicated making a person less aware of their surroundings and less likely to be able to maintain control of situations, for example, not being able to look after their belongings or to negotiate safe sex.
  • substituting one drug for another people trying to cut back on one drug may end up using more of the other to help manage the symptoms of reducing the first drug. For example, some people giving up cannabis may find it difficult to sleep and start drinking alcohol at night to help them sleep and vice-versa. This type of drug use is risky and can result in a person having problems with two drugs instead of one...

Factsheet updated 11 July 2016.