The caffeine in coffee can worsen heart disease, high cholesterol, hypertension, indigestion, mood swings and a whole slew of other conditions. Even though tea contains caffeine, less of it winds up in the finished brew. Both green and black teas are made from the same plant , Camillia sinensis , an attractive shrub. For green tea the leaves are briefly steamed, then dried. Scented teas are mixed with dried flower petals and essential oils.
Green tea is definitely the better choice of the two.
Recently, researchers led by Jerzy Jankun of the Medical College in Ohio were able to show the primary mechanism by which this drink helps protect you from cancer. Green tea contains a chemical called EGCG . This compound blocks an enzyme called urokinase, which assists tumor growth by attacking the cells surrounding the cancer. Black tea doesn't contain EGCG, probably because it breaks down in the fermentation process. Still, black tea does have other cancer-fighting polyphenols, which are believed to act as antioxidants, scooping up the free radicals that harm cells.