Alcohol – general information

Learn more about alcohol including how it affects your body, how much alcohol is in a standard drink and how to check if your drinking is okay.

What is alcohol?

Alcohol (ethanol or ethyl alcohol) is the ingredient found in beer, wine and spirits that causes intoxication or an altered state. It is a chemical compound that is generally tolerable in small amounts, but is poisonous to the human body in large amounts.

When alcohol is swallowed, it is rapidly absorbed into your bloodstream and distributed to all parts of your body within just a few minutes. As it reaches different parts of your body, alcohol slows down the work of your cells, especially in your brain. You can feel this happening in the symptoms of the stages of intoxication and drunkenness – relaxation, laughter, slurred speech, inability to walk straight, and impaired judgement and coordination.

As alcohol travels through your stomach and intestines to your liver, it starts to be broken down (metabolised). Enzymes in your liver work hard to clear it from your body, taking 1 to 2 hours to break down 1 standard drink. 

Effects of alcohol on your body

At low doses, alcohol can act as a stimulant that induces feelings of euphoria and talkativeness. However, it is classed as a central nervous system (CNS) depressant, which means it depresses your central nervous system at high doses and slows down your body’s reaction times and responses.

People respond to alcohol in individual ways, and the same amount of alcohol consumed can have varying effects on different people. Your reaction to alcohol is influenced by:

  • the ability of your liver to break down alcohol
  • your stomach contents or recent food consumption
  • how much alcohol you have had and how quickly you have drunk it
  • your body type and age, gender and ethnicity.

Drinking too much alcohol at one session can lead to drowsiness, respiratory depression (where your breathing becomes slow, shallow or stops entirely), coma or even death.

Use this interactive tool or click below to find evidence-based detail from the HPA of how alcohol affects body systems and parts:

See also:

What is a standard drink?

It’s not the amount of liquid you’re drinking that’s important – it’s the amount of alcohol.

Standard drinks are a useful and simple way to monitor how much alcohol you are drinking. Standard drinks provide a measure of the amount of pure alcohol in a drink.

Image credit: alcohol.org.nz

A standard drink = 10g of alcohol. This is how much alcohol is typically found in:

  • 330 ml can of standard beer
  • 100 ml small glass of wine
  • 30 ml shot of straight spirits.

Standard drinks information can be found on a bottle, can or cask. The strength of the alcohol is important in this. 

When not to drink alcohol

There are times and circumstances when it is advisable not to drink alcohol.

You should not drink if you:

  • are pregnant or planning to get pregnant
  • are on medication that interacts with alcohol
  • have a condition made worse by drinking alcohol
  • feel unwell, depressed, tired or cold, as alcohol could make things worse
  • are about to operate machinery or a vehicle or do anything that is risky or requires skill.

Learn more about low-risk drinking.

Is my drinking okay?

Drinking too much at one go (binge drinking) or drinking too much over time (alcohol misuse) can both lead to long-term health problems.

The Health Promotion Agency’s Is Your Drinking Okay? test can help you find out more about your level of risk from your drinking. Just complete the questionnaire and it will automatically add up your score and tell you what it means. It's that easy! 

Take the test: Is your drinking okay?

A range of factors can affect your level of risk, including the rate of drinking, your body type or genetic makeup, your gender, existing health problems and whether you are young or an older person.

Learn more about harmful drinking, low-risk drinking and advice for parents.

Learn more about alcohol

Alcohol Health Promotion Agency, NZ
Alcohol and you – an NHS self help guide NHS, UK

Reviewed by

Klare Braye has been in the alcohol and drug/addiction space for over 25 years. Reducing the stigma, ensuring access to supports, considering flexible and responsive treatment options and engaging tangata whai ora and whānau are integral to the mahi in this space. Klare has worked in a variety of settings providing support, clinical input, education and research.  
Credits: Health Navigator Editorial Team. Reviewed By: Klare Braye, Principal Clinical Advisor, Addictions, Ministry of Health Last reviewed: 28 Jun 2019