Caffeine is a naturally occurring substance found in the leaves, seeds or fruits of at least 63 plant species worldwide. The most commonly known sources of caffeine are coffee, tea, some soft drinks and chocolate. The amount of caffeine in food products varies depending on the serving size, the type of product and preparation method. With teas and coffees, the plant variety also affects caffeine content.


This article is about the chemical substance caffeine. For other uses, see ...
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  • Caffeine (National Women's Health Information Center)
  • Caffeine (Nemours Foundation)