The traditional method of endometrial biopsies uses a specialized catheter (the Pipelle) to suction away a portion of the uterine lining. The Tao brush method instead uses a small, flexible brush to gently brush the entire inside of the uterus. The Tao brush is theoretically able to gather a more complete sampling of the uterus lining, removes less tissue, and some reports suggest that it is less painful than the traditional method.