41. ___41___. It is a member of the xanthine group of chemicals, whick also includes theophylline, an ingredient used in asthma medication, and theobromine, found in tea and cola drinks. The first verifiable use of caffeine was more than 2,000 years ago among Ethiopian tribesmen who ate a mixture of raw coffee beans and fat. Caffeine has no real nutritional role, but millions of people worldwide insist they " can't get started" without a morning cup of coffee. To these people, it is, indeed, important. Recent studies confirm what many caffeine users have long been know ---- the substance is addictive and those who try to give it up suffer withdrawal symptoms. Fortunately, caffeine addiction is relatively benign, especially when compared addictions to nicotine, alcohol, or illegal drugs.