Description

Alcohol is a liquid obtained through the fermentation of certain fruits or cereals, or through distillation, which is a process of condensation most often conducted using heat. It is a component of various beverages, including beer, coolers, wine, cider, aperitifs, liqueurs and spirits.

Alcohol is a psychoactive substance that is a depressant. This type of drug affects the central nervous system by numbing the brain and slowing the body. It affects, among other things, behaviour and coordination.

A standard drink is equivalent to:

  • A 341 mL (or 12 oz) can or bottle of beer at 5% alcohol by volume
  • A 142 mL (or 5 oz) glass of wine at 12% alcohol by volume
  • A 43 mL (or 1.5 oz) glass of spirits at 40% alcohol by volume
  • An 85 mL (or 3 oz) glass of fortified wine at 20% alcohol by volume

You can use these values to assess how much you are drinking and make informed decisions about your drinking.

Effects of alcohol

How alcohol affects a person is influenced by the law of effect, which is the interaction of the following three factors:

  • The individual
  • The context in which he or she consumes
  • The product or substance being consumed

Drinking fast or on an empty stomach speeds up the effects of alcohol. Smaller-statured and tired individuals also experience the effects of alcohol much quicker. To learn more, read the section Effects of drugs.

About an hour after the first drink, a person may:

  • Feel relaxed
  • Be a little more talkative than usual
  • Be less shy
  • Feel a sense of pleasure
  • Become more emotional, more sentimental and more excited

Alcohol can also induce:

  • Impaired judgment
  • Delayed reactions
  • Blurred vision
  • Digestive problems, nausea or vomiting
  • Loss of balance, difficulty or inability to walk
  • Confused or incomprehensible speech
  • Anger or depression
  • Difficulty or inability to organize thoughts

There is no way to prevent alcohol from mixing with blood or precipitate an end to its effects. You must wait for the body to get rid of the alcohol by itself, based on your characteristics (e.g., gender, weight, height, health, etc.).

Alcohol and young people

Drinking alcohol can impair the physical and mental development of young people. Teenagers are more likely to feel the effects than adults, as their personality structure and brain are still developing. They should wait as long as possible before having their first drink.

To learn more, go to the page Alcohol consumption, drug use and gambling: helping teenagers.

Risks associated with drinking and possible consequences

Higher risk of serious illnesses

Based on current knowledge, even a small amount, can have health and safety risks. It increases the risk of developing at least seven types of cancer and about 200 diseases, in addition to increasing the risk of injuries or accidents for yourself and others.

For example, drinking one glass a day or more significantly increases the risk of developing several types of cancer:

  • Breast cancer
  • Colon cancer
  • Esophageal cancer
  • Laryngeal cancer
  • Liver cancer
  • Mouth cancer
  • Pharynx cancer

Drinking alcohol also increases the risk of developing many diseases, in addition to increasing the risk of accidents or injuries:

  • Cardiovascular diseases: stroke, coronary artery disease, heart failure, fatal hypertensive disease and fatal aortic aneurysm
  • Gastrointestinal diseases: liver disease, cirrhosis, pancreatitis
  • Infectious diseases: sexually transmitted and blood-borne infections (STBBIs), pneumonia, tuberculosis
  • Neurological and neuropsychological conditions: epilepsy, depression, dementia, alcohol-induced psychosis
  • Acute alcohol poisoning: alcohol abuse that can endanger people's lives
  • Intentional and unintentional injuries: homicide, suicide, interpersonal violence, road accidents, work accidents, drownings, falls

To find out how to reduce the risks associated with drinking alcohol, go to the page Reducing the health and safety risks of drinking alcohol.

Impact on behaviour and judgment

Drinking can affect behaviour and judgment. The person who drinks may do things he or she would not normally do or make decisions he or she would not normally make. For instance, the person could:

  • Say hurtful things to a loved one
  • Drive under the influence of alcohol or think there is little risk in getting into a vehicle driven by someone who is also drunk.
    Driving a vehicle under the influence of alcohol is dangerous and can lead to penalties and the opening of a criminal record. To find out more, go to the website of the Société de l'assurance automobile du Québec
  • Post images and words on social media that could be harmful to loved ones or an employer when they see or find out about them
  • Behave violently, sometimes even with a loved one
  • Have unprotected sex, which could lead to an unplanned pregnancy or a sexually transmissible infection
  • Do things that can cause harm to himself or herself or other people, such as committing an offence

Additionally, drinking in a prolonged and regular way, or in large quantities, can lead to other consequences:

  • Violent behaviour (physical, sexual, psychological, etc.)
  • Problems at school, work and with loved ones
  • Risky sexual behaviour
  • Addiction
  • Accidents, injuries and death
  • Suicide

Addiction

Alcohol can lead to psychological and physical dependency.

With a psychological dependency, the person usually needs to drink more and more in order to feel better about himself or herself, relax, calm down, feel stimulated or have the courage to face problems.

With a physical dependency, a physiological need is created by the body’s addiction to the effects of the alcohol. If person tries to go without it, he or she may experience varying degrees of physical reaction, such as:

  • Anxiety, panic, irritability
  • Restlessness
  • Delirium
  • Insomnia
  • Excessive sweating
  • Shaking
  • Seizures (stiff body with jerky and involuntary muscle spasms)
  • Nausea and vomiting
  • Confusion
  • Hallucinations

To learn more, consult:

Risks associated with binge drinking

Binge drinking is heavy consumption of alcohol over a short period. This practice can have serious consequences:

  • Persistent vomiting
  • Difficulty breathing
  • Loss of consciousness
  • In the most serious cases, death

Someone who has drunk a lot of alcohol should never be left alone.

To learn more, read the Intoxication section of Problems Associated with alcohol consumption and drug use.

Mixing alcohol with other substances

Mixing alcohol with other substances, such as other drugs, energy drinks or medication, can be dangerous. Such combinations can produce unpredictable effects and cause significant harm.

To learn more, read Alcohol and other drugs: a combination to avoid.  

Help and resources

For help or information on alcohol consumption, resources are available:

For more information, visit the website of your integrated health and social services centre (CISSS) or integrated university health and social services centre (CIUSSS). To find a CISSS or CIUSSS near you, go to the page Find your integrated health and social services centre (CISSS) or integrated university health and social services centre (CIUSSS).

Last update: February 10, 2026

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