Last updated : April 27, 2017
Caffeine is a stimulant drug, which means it speeds up the messages travelling between the brain and the body.
It’s found in the seeds, nuts and leaves of a number of different plants, including:
Caffeine is used in a number of different products. The amount of caffeine in these products can vary dramatically, so it’s always best to check the label. The average amounts are listed below.
|Product||Average caffeine content (mg/100 ml)|
|Brewed black tea||22.5|
|Brewed green tea||12.1|
|Coffee, flat white||86.9|
|Coffee, long black||74.7|
|Coffee, from ground coffee beans, espresso style||194.0|
|Chocolate, milk with added milk solids||20.0|
|Chocolate, dark, high cocoa solids||59.0|
Adapted from Food Regulation Standing Committee, Caffeine Working Group. (2013). The regulation of caffeine in foods.
*The Cocoa-Cola Company. (2015). Caffeine: Your questions answered.
There is no safe level of drug use. Use of any drug always carries some risk. It’s important to be careful when taking any type of drug.
Caffeine affects everyone differently, based on:
The following effects may be experienced between 5 to 30 minutes after consuming caffeine, and may continue for up to 12 hours:
Children and young people who consume energy drinks containing caffeine may also suffer from sleep problems, bed-wetting and anxiety.4
If a large amount of caffeine is consumed it could also cause an overdose. If you experience any of the following effects, call an ambulance straight away by dialling triple zero (000).
It’s possible to die from having too much caffeine, but this is extremely rare. This would usually only happen if 5–10g of caffeine (or 80 cups of strong coffee) were consumed one after the other.1
In small children, caffeine poisoning can happen if a lower amount, such as around 1g of caffeine (equal to around 12 energy drinks) is consumed one after the other.6
Some people consume drinks with caffeine so that they can continue working or studying at night. However, the after-effect is that they will feel tired and lethargic the next day.
Regular, heavy use of caffeine (such as more than 4 cups of coffee a day) may eventually cause:
The effects of taking caffeine with other drugs – including over-the-counter or prescribed medications – can be unpredictable and dangerous, and could cause:
Caffeine + alcohol: enormous strain on the body, and can mask some effects of alcohol such as falling asleep, leading to drinking more and risk taking behaviour.
Caffeine + other stimulant drugs: increase the risk of cardiovascular problems.7
Giving up caffeine after using it for a long time is challenging because the body has to get used to functioning without it. Withdrawal symptoms usually start within 24 hours after the last dose – or even within 6 hours for people who consume a lot of caffeine regularly. The symptoms can last for around 36 hours, or even longer for people who consume a lot.
These symptoms can include: