How much caffeine is too much?

Caffeine is a stimulant drug that acts on the nervous system, like others drugs you can become addicted....'

Your susceptibility to caffeine depends on your body mass, state of health, metabolism, and whether or not your body is used to getting regular doses of caffeine. Generally speaking, 500mg per day or less is considered an acceptable dose of caffeine.

Approximate caffeine levels per serve include:

Chocolate drinks – 30 to 60mg
Instant coffee – 60 to 100mg
Drip or percolated coffee – 100 to 150mg
Espresso coffees – such as espresso or latte – 90 to 200mg
Cola drinks – 35mg
Decaffeinated coffee – around 3mg
Tea – 30 to 100mg, depending on the type and strength of the brew
Energy or sports drinks – such as Red Bull or ‘V’ – 80 to 90mg
Dark chocolate bar – 40 to 50mg per 55g serve
Guarana – can contain up to 100mg per one gram of guarana Caffeine tablets – such as No-Doz – 100mg per tablet.

For more information, please visit
http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Caffeine?open&source=homepage&linktype=Topics-Quote&ppnl=Topics&ppos=Quote