Alcohol and illegal drugs

Alcohol affects your body in many different ways. Adding illegal drugs into the mix can have unpredictable – even fatal – consequences. Find out more here.

Alcohol is recognised as a ‘psychoactive substance’ by the World Health Organization because of how it affects your brain, the way you think and feel, and your health.¹

Illegal drugs are psychoactive substances too and have a wide range of different dangerous health effects on their own.² If you drink alcohol and take drugs at the same time, or close together, it can have serious consequences for your health as the different substances interact with each other and with your body. The effects can even be fatal.³

The best advice is not to take illegal drugs at all. If you do drink alcohol, you should never combine it with illegal drugs and always stick to the UK Chief Medical Officers’ (CMOs’) low risk drinking guidelines.⁴

If you or someone else needs urgent help after taking drugs or drinking, call 999 for an ambulance. Tell the crew everything you know. It could save their life.

What happens in the body?

Alcohol is a depressant, which means it alters the delicate balance of chemicals in your brain and interferes with processes in your central nervous system.⁵

All illegal drugs have different effects of their own, which are dangerous in their own right – including depressants like heroin and ketamine. If you have alcohol with another depressant, it can multiply the effect – putting your body at increased risk.^6,7

Some other illegal drugs have a ‘stimulant’ effect, like cocaine, ecstasy (MDMA), and other amphetamines. Combining a stimulant with alcohol can cause additional stress on your body which can be dangerous.^8,9

If you’re under the influence of drugs you are less likely to make considered decisions about how much alcohol you drink – these lowered inhibitions put you at risk of acute alcohol poisoning.^10,11

And with no quality control in the world of illegal drugs, you can never be sure of exactly what you’re taking – they can be mixed or contaminated with other harmful substances. Drinking alcohol at the same time, adds a further risk factor to what is already a potentially lethal cocktail.

Here are some facts about what can happen when you mix certain illegal drugs with alcohol.

People who smoke while consuming alcohol, including at low levels, increase their risk of head and neck cancer compared to drinking alcohol alone. As alcohol consumption and smoking increase, the effect on cancer risk becomes greater.¹²

Alcohol and cannabis

Cannabis (also called marijuana or weed) is the most used illegal drug in the UK.¹³ It can have a variety of effects on people ranging from feelings of relaxation to being lethargic or paranoid, confused, or anxious.¹⁴

If you use cannabis and alcohol together, the results – both physical and psychological – can be unpredictable. Drinking alcohol at the same time as using cannabis can make some people feel nauseous or even vomit.¹⁵

Never drive after smoking cannabis or drinking alcohol. You are more likely to have an accident – and if you combine the two, the danger is even greater.¹⁶

Both cannabis and alcohol can affect your mental health too and are linked to causing feelings of panic, anxiety, paranoia, and depression.^17,18 Skunk, a term for stronger types of cannabis, can pose even greater risks.¹⁹

And because of the way alcohol interferes with your ‘fight or flight’ response,²⁰ drinking can make you more vulnerable to anxiety^21,22 and make symptoms worse.²³

Cannabis is usually smoked with cancer-causing tobacco too, and if you use tobacco together with alcohol there is a multiplying effect on your risk of cancer because of the way they interact.²⁴

Alcohol and stimulants

Alcohol and cocaine

Taking alcohol and cocaine together increases the risk of heart attacks, fits, and even sudden death.

When alcohol and cocaine are taken together, they interact to produce a highly toxic substance in your liver called cocaethylene. It increases the depressive effects of alcohol on your nervous system – making your reaction to the cocaine stronger and more dangerous, and increasing the risk of cocaine-associated heart attacks.²⁵

Cocaethylene takes longer to get out of your system than either alcohol or cocaine if taken on their own. This means your heart and liver are exposed to a longer period of stress – mixing alcohol and cocaine can be fatal up to 12 hours after you’ve taken them.²⁶

Alcohol and ecstasy (MDMA)

Ecstasy (also known as MDMA) is a stimulant which can make people feel energised and uninhibited, while also raising body temperature and heart rate. It can contribute towards feelings of depression, anxiety, and cause panic attacks for some people.²⁷

Ecstasy dehydrates you. So does alcohol because it’s a ‘diuretic’ which means it makes you pee and sweat more.²⁸ This makes it harder to keep enough fluid in your body. If you drink alcohol while taking ecstasy, you risk overheating and becoming dangerously dehydrated when you combine the two.²⁹

Both MDMA and alcohol damage your liver too. The liver is the organ that sustains the greatest degree of tissue damage through heavy drinking, which leads to alcohol-related liver disease.^30,31

Dehydration can become serious and lead to confusion and seizures. Serious dehydration requires urgent medical attention.³²

Long-term use of MDMA has also been found to have links to anxiety and depression.^33,34 Long-term heavy drinking negatively impacts your mental health too^35,36– so combining the two means there’s more than one way you’re increasing the risk to your mental health.

Alcohol and amphetamines

Amphetamines – often called ‘speed’ – are a stimulant which as well as creating feelings of alertness and increasing your heart rate, can increase your blood pressure.³⁷

Taking any stimulant which makes you feel more alert can make you less aware of the effect of any alcohol you drink,³⁸ so you may end up drinking more than you realise – putting you at greater risk of acute alcohol poisoning.³⁹

Both amphetamines and alcohol reduce your inhibitions too, you are more likely to do something you regret – and you are putting yourself at greater risk of accidents.^40,41

And just like ecstasy, amphetamines can also increase your body temperature and are linked to dehydration – which is heightened when you add alcohol.^42,43 As amphetamines already put a lot of pressure on your heart, adding alcohol can be fatal.⁴⁴

Any medication you have been prescribed by a doctor is not illegal for your own use. Depending on what you’re taking and your health condition, drinking can make medication less effective or lead to dangerous health consequences. Always consult with your doctor or pharmacist if you think you might want to drink any alcohol.⁴⁵

Alcohol and depressants

Alcohol and heroin, and other opiates

Alcohol with heroin is one of the most dangerous combinations of drugs.

Using heroin with other drugs or alcohol increases the risk of an overdose which can lead to a coma or death.⁴⁶

Heroin – as well as other opiates like methadone – slows down your heart rate and breathing.^47,48 As alcohol is also a depressant, if you combine the two, your risk of overdose increases.⁴⁹You are also at greater risk of choking if you vomit, as both drugs together impair your gag reflex.⁵⁰

Alcohol and benzodiazepines

Benzodiazepines (‘benzos’, diazepam, Valium or Xanax) are a type of depressant, which are sometimes given as a prescription from your doctor to treat anxiety. Possession of these types of drugs in the UK is illegal without a prescription. There are also illegally produced ‘street benzos’ which are similar but can be far more dangerous.⁵¹

Taking benzodiazepines can make you drowsy, dizzy, and sometimes aggressive. Taking them with alcohol is dangerous and increases your risk of overdose and death. That’s because they both depress your central nervous system, which affects your breathing and gag reflex.⁵²

These types of drugs have also been implicated in some cases of drink spiking.^53,54

Alcohol and other illegal drugs

The different types of illegal drugs have increased rapidly over recent years, due to substances known as ‘new psychoactive substances’ (NPS). Often referred to as ‘legal highs’, these have been illegal since 2016.⁵⁵

The wide range of substances in this category means they can have a wide range of very different effects. For example, prominent types of NPS include a stimulant called mephedrone (‘meow meow’) and a synthetic cannabinoid called ‘spice’. Mixing them with alcohol is dangerous – it’s impossible to definitively say exactly how they will react if you mix them together.^56,57

The best advice is not to take any illegal substances, and to avoid alcohol with them if you do.

Drink spiking

Different types of spiking can include the following substances being added to drinks:

Alcohol
‘Date rape’ drugs
Illegal drugs
Prescription drugs (e.g. stimulants, tranquillisers, sedatives, opiates)

Spiking a drink – whether with an extra shot of alcohol or another substance – is a serious crime. Anyone that does it could face serious criminal charges, and it can have very dangerous consequences for the health of the person whose drink is spiked.⁵⁸

Find out more about drink spiking and how you can stay safe.

Drink spiking and date rape drugs

If you want to know more about your drinking habits, our Drinking Check below can help you identify if the amount you drink could be putting your health at risk.

External links to support

In an emergency, if you or someone else needs urgent help after taking drugs or drinking, call 999 for an ambulance. Tell the crew everything you know. It could save their life.

If you need urgent help outside of a medical emergency: