This NBC News article explores the common substance, caffeine, and looks at both its benefits and ways it can be dangerous. After one man in California was arrested and charged with a DUI, yet only had caffeine in his bloodstream at the time of the altercation, is there more to this seemingly innocent substance we should be aware of? It doesn’t seem so. While overdoing it with caffeine consumption can cause some unpleasant side effects, a moderate intake of the substance can actually improve mental focus, athletic performance, and give you an afternoon boost of energy.