Drink up. Tea has so many benefits. Caffeine, taken moderately, stimulates the central nervous system and promotes blood circulation. It aids elimination by performing as a diuretic to ensure better functioning of the kidneys. By drinking tea regularly, one may reduce the incidence of Gallstones
and other kidney problems.
Do your cleanses regularly if you have a fear of the tannic to gallstone relationship - but I have never seen any concrete study indicating such. Medline has no studies showing this.