Caffeine is one of the best-known orally consumed drugs in the world. In 1820, 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 the diet of adults, while caffeinated soft drinks are the main sources of caffeine in the diet of children 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 to human health. Caffeine is an alkaloid that is a pharmacologically active substance consumed by many 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 an essential role by being the necessary ingredient in beverages such as coffee, soft drinks, tea, energy drinks and even in foods such as chocolate. The composition level of caffeine in foods and drinks depends mainly on the plant variety from which it is derived, the portion size, the brand and the preparation method. Table 1: The table above shows the general composition of caffeine in some foods and drinks. Caffeine is absorbed from the gastrointestinal tract into the bloodstream and reaches its maximum concentration in the blood within 1-1.5 hours of ingestion [7]. Caffeine's effect on the body is largely due to its binding to the adenosine receptor. Adenosine is a neuromodulator of the central nervous system that has specific receptors [3]. Neural activity...... middle of paper...... www.foodinsight.org/Content/3147/Caffeine_v8-2.pdf [Accessed: 10 October 2013].[5] Miller, A. 2011. Does caffeine affect dopamine levels?. Available at: http://www.livestrong.com/article/454154-does-caffeine-affect-dopamine-levels/ [Accessed: 30 October 2013].[6] Miadipendenza.com. nd History of caffeine. Available at: http://www.myaddiction.com/education/articles/caffeine_timeline.html [Accessed: 30 October 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: 10 October 2013].[8] Reynolds, G. 2011. How Coffee Can Galvanize Your Workout. Available at: http://well.blogs.nytimes.com/2011/12/14/how-coffee-can-galvanize-your-workout/?_r=1 [Accessed: October 30 2013].