I don't know much about tea, but too much coffee can be bad for your health. My best friend's brother take 4 cups in a day everyday. Just 2 weeks ago, he passed out. An ecg (electrocardiogram) was applied to him to check the status of his heart. It was found out that he had PVC or premature ventricular contraction and ___ flutter. I just forgot the term for the other one. Basing on his lifestyle, he does nothing else to have such condition but his too much drinking of coffee. The caffeine that does the damage. It has effects on most physiologic body functions.