Coca, often associated with the coca plant, is a source of the stimulant cocaine, but it also contains caffeine. Caffeine is a natural compound found in various plants, known for its ability to enhance alertness and reduce fatigue. It is commonly consumed in beverages like coffee and tea. Caffeine works by blocking the effects of adenosine, a neurotransmitter that promotes sleep, thereby increasing energy levels. While it is generally safe in moderate amounts, excessive consumption can lead to side effects such as anxiety, insomnia, and increased heart rate.