Tea has caffeine too, but about half as much
"
CAFFEINE PER 6-OZ. CUP, IN MILLIGRAMS
Espresso (2 oz) 60-90 mg
Drip coffee 60-180 mg
Black tea 25-110 mg
Green tea 8-16 mg
Herbal tea 0 mg
Oolong tea 12-55 mg
White tea 5-15 mg
Rule of thumb, a cup of black tea has *about* half the caffeine as a cup of coffee. Even decaf coffee has 3-4 mg of caffeine per cup. "
Here is some info about affects on health
http://www.hflsolutions.com/ne/free_...lems_Top10.pdf