Caffeine is one of the most well-known oral drugs in the world. In the 1820s, a German chemist named Friedrich Ferdinand Runge first discovered caffeine by extracting it from coffee [6]. Coffee and tea are the main sources of caffeine in adult diets, while caffeinated soft drinks are the main sources of caffeine in children's diets in North America [7]. The per capita level of caffeine consumption for consumers of all ages is approximately 120 mg/day [4]. The purpose of this investigation is to conclude whether regular caffeine consumption is beneficial for human health. Caffeine is an alkaloid that is a pharmacologically active substance consumed by many people around the world [7]. This chemical acts as a central nervous system (CNS) stimulant that suppresses drowsiness and promotes alertness. It is a natural substance commonly found in tea leaves, coffee beans, cocoa beans, kola nuts and other plant species [7]. Today, caffeine plays a vital role by being a necessary ingredient in beverages like coffee, soft drinks, tea, energy drinks as well as foods like chocolate. The caffeine content of foods and drinks mainly depends on the plant variety from which it is derived, serving size, brand and brewing method. Table 1: The table above shows the general composition caffeine in some foods and beverages. Caffeine is absorbed from the gastrointestinal tract into the bloodstream and reaches its peak concentration in the blood within 1 to 1.5 hours after ingestion [7]. Caffeine's effect on the body is largely due to its binding to the adenosine receptor. Adenosine is a central nervous system neuromodulator with specific receptors [3]. Neural activity...... middle of article ......www.foodinsight.org/Content/3147/Caffeine_v8-2.pdf [Accessed: October 10, 2013].[5] Miller, A. 2011. Does caffeine affect dopamine levels?. Available at: http://www.livestrong.com/article/454154-does-caffeine-affect-dopamine-levels/ [Accessed: October 30, 2013].[6] Maaddiction.com. nd History of caffeine. Available at: http://www.myaddiction.com/education/articles/caffeine_timeline.html [Accessed: October 30, 2013].[7] Nawrot, P., Jordan, S., Eastwood, J., Rotstein, J., Hugenholtz, A. and Feeley, M. 2003. Effects of caffeine on human health. Available at: http://www.researchgate.net/publication/10957470_Effects_of_caffeine_on_human_health/file/79e41508e60e522c2a.pdf. [Accessed: October 10, 2013].[8] Reynolds, G. 2011. How Coffee Can Supercharge Your Workout. Available at: http://well.blogs.nytimes.com/2011/12/14/how-coffee-can-galvanize-your-workout/?_r=1 [Accessed October 30 2013].