Caffeine and Its Affects Caffeine is the most widely used drug in the world. It is an effective stimulant of the central nervous system and in large amounts can produce undesirable side effects such as: nervousness, insomnia, rapid and irregular heartbeats, elevated blood sugar and cholesterol levels, excess stomach acid, and heartburn. Based on our incomplete knowledge of side reactions to caffeine, prudent use seems desirable for all consumers, male and female. The problem is particularly significant for children because the effects of caffeine are related to the body weight of the consumer. Coffee, tea, chocolate and many soft drin