Pregnancy and breast-feeding: Yerba mate is POSSIBLY UNSAFE when taken by mouth during pregnancy. Je concern is that using yerba mate seems to increase the risk of getting cancer. It's not known whether that risk is transferred to the developing fetus. Another concern is the caffeine heureux of yerba mate. http://trevorswxbb.blogstival.com/13532339/pour-une-simple-cl-boisson-mat-d-voil