Please note: The information given on this page is not medical advice and should not be relied on in this way. Individuals wanting medical advice on this issue should consult a health professional.
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:
How is caffeine used?
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, but the average amounts are listed below.
Adapted from Food Regulation Standing Committee, Caffeine Working Group. (2013). The regulation of caffeine in foods.
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 any of the following effects are experienced an ambulance should be called straight away by dialling triple zero (000).
It is possible to die from having too much caffeine, but this is extremely rare. This would usually only happen if 5–10 grams 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 1 gram 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:
Using caffeine with other drugs
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:
Reducing the risks
1. Brands, B., Sproule, B., & Marshman, J. (Eds.). (1998). Drugs & drug abuse (3rd ed.). Ontario: Addiction Research Foundation.
2. Food Standards Australia New Zealand. (2014). Caffeine.
3. Upfal, J. (2006). The Australian drug guide. (7th ed.). Melbourne: Black Inc.
4. Seifer, S., Schaechter, J., Hershorin, E. & Lepshultz, S. (2011). Health effects of energy drinks on children, adolescents, and young adults. Pediatrics, 127(3). 511–528.
5. NPS Medicinewise. (2013). What's the buzz with energy drinks?
6. Nawrot, P., Jordan, S., Eastwood, J., Rotstein, J., Hugenholtz, A. & Feeley, M. (2003). Effects of caffeine on human health. Food Additives and Contaminants, 20(1). 1–30.
7. Arria, A., Calderia, K., Kasperski, S., O'Grady, K., Vincent, K., Griffiths, R. & Wish, E. (2010). Increased alcohol consumption, nonmedical prescription drug use, and illicit drug use are associated with energy drink consumption among college students. Journal of Addiction Medicine, 4(2). 74–80.
8. American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders. (5th ed). Washington: American Psychiatric Publishing.
Last updated: 5 May 2016