Caffeine, is it a helpful drug or a hazardous toxin? Caffeine is a naturally occurring substance. It is found in seeds, leaves or fruits in about 60 plants. Beverages with caffeine in them have been consumed since 2700B.C.. People all over the world consume caffeine every day. Many people have various ideas on the way caffeine affects the human body. Some experts say it prevents cancer while others say caffeine makes people more prone to cancer. You decide. In the article What You Should know About Caffeine, printed in the Information Food Council Foundation, states that caffeine has no relevance to many forms of cancer and other problems. These diseases include cardiovascular disea