[doctornemo]

It does not, according to the various medical people I asked. Alas, I still don't like the taste.

[Tichy]

Hm, weird, can't imagine that is true. So where does the caffeine in black tea come from?

[krallja]

Brewed green tea contains 24-40mg of caffeine per 240mL; brewed black tea contains 14-61mg of caffeine per 240mL.

http://www.mayoclinic.com/health/caffeine/AN01211