Caffeine is a drug which comes from the leaves, beans or nuts of different plants. Caffeine is a stimulant drug. This means it speeds up the brain and nervous system.​

Last updated: 11 July 2013

What is caffeine?

Caffeine is a drug which comes from the leaves, beans or nuts of different plants. Caffeine is a stimulant drug. This means it speeds up the brain and nervous system.

The most common things containing caffeine are:

  • coffee
  • tea
  • cocoa
  • chocolate
  • cola drinks.

Effects of caffeine

Small amounts of caffeine (less than 600 mg per day) are not harmful. See the caffeine chart at the end of this fact sheet to measure how much caffeine you have.

What caffeine does to you depends on:

  • how much you have
  • your height and weight
  • your general health
  • your mood
  • whether you have caffeine often
  • whether you have caffeine on its own, with food or with other drugs.

Immediate effects

Small amounts

When you have a small amount of caffeine (such as a cup of coffee):

  • you feel more awake
  • your heart beats faster
  • you urinate more
  • your body temperature rises
  • your digestive system produces more acid.

Large amounts

If you have a large amount of caffeine, you might:

  • get headaches
  • feel restless
  • feel nervous
  • become delirious (be confused, have hallucinations or be very excited)
  • find it difficult to sleep.

Long-term effects

If you have more than 600 mg of caffeine a day for a long time you may:

  • find it difficult to sleep
  • worry a lot
  • be depressed
  • have stomach upsets.

For people who already have heart problems or anxiety disorders such as panic attacks or agoraphobia (being afraid of public places or open spaces), large amounts of caffeine may make the problems worse.

Caffeine and sleep

If you have caffeine before you go to bed, it usually:

  • makes it harder to get to sleep
  • makes you sleep for a shorter time
  • shortens the amount of deep sleep you have
  • gives you more 'dream sleep' at first, but less overall. Both deep sleep and dream sleep are important for proper rest.

Caffeine and pregnancy

Having caffeine when you are pregnant is safe if you have normal amounts of caffeine. However, very large amounts of caffeine during pregnancy may lead to losing the baby, the baby being born too early or being born dead. Doctors recommend that pregnant women have no more than two to four cups of coffee or tea (about 200 mg of caffeine) a day.

Tolerance and dependence

Anyone can develop a 'tolerance' to caffeine. Tolerance means that you must have more of the drug to feel the same effects you used to have with lower amounts. 'Dependence' on caffeine means that it takes up a lot of your thoughts, emotions and activities. Not all people who take caffeine are dependent.


People who are dependent on caffeine may experience withdrawal symptoms if they try to stop or cut down the amount of caffeine they have.

Withdrawal symptoms can include:

  • headaches
  • feeling angry or upset
  • tiredness.

Caffeine chart

There is very little risk of harm if you have less than 600mg of caffeine a day. If you are worried or stressed, or if you are pregnant, have less than 200mg (2-4 cups of coffee or tea) a day.

ProductHow much caffeine?Comments
Instant coffee60-100 mg per cupThe amount of caffeine depends on how much you put in the cup
Fresh coffee80-350 mg per cupThe amount of caffeine depends on:
  • the type of beans ('Robusta' contains more caffeine than 'Arabica')
  • the way the coffee is made
  • how strong the brew is

Decaffeinated coffee2 - 4 mg per cupThe amount of caffeine is usually marked on the packet
Tea8 - 90 mg per cupCaffeine content depends on how strong the brew is
Cola drinks35 mg per 250ml serve Cola drinks often contain a lot of sugar too
Cocoa and hot chocolate10 - 70 mg per cupThe amount of caffeine depends on strength of the brew and the other chemicals in the product
Chocolate bars20 - 60 mg per 200 g barChocolate also contains a lot of sugar
Some prescription and over-the-counter medications20 - 100 mg per doseSome medicines (cough, headache and slimming products) contain caffeine.

Further information

Drug and alcohol service intake numbers

These centralised numbers are the first point of contact for people seeking assistance for drug and alcohol problems. Callers may be assessed by telephone and referred to relevant services within the local health district.

Centralised intake lines operate Monday to Friday during business hours.

Metropolitan local health districts

Northern Sydney/Central Coast
  • North Sydney - 1300 889 788
  • Central Coast - (02) 4394 4880
South Eastern Sydney/Illawarra
  • South East Sydney - (02) 9113 4444
  • Illawarra - (02) 1300 652 226
Sydney South West
  • South West Sydney - (02) 9616 8586
  • Central Sydney - (02) 9515 6311
Sydney West
  • Wentworth - (02) 4734 1333
  • Western Sydney - (02) 9840 3355

Rural local health districts

Greater Southern
  • Greater Murray - 1800 800 944 or (02) 9425 3923
  • Southern - 1800 809 423
Greater Western
  • Far West - 1800 665 066 or 08 8080 1556
  • Macquarie - 1800 092 881 or (02) 6841 2360
  • Mid Western - 1300 887 000
Hunter/New England
  • Hunter - (02) 4923 2060
  • New England - 1300 660 059
North Coast
  • Local health district - 1300 662 263
  • Mid North Coast - (02) 6588 2882
  • Northern Rivers - (02) 6620 7612
Current as at: Thursday 11 July 2013