In microvascular surgery and surgery of the hand, hemostasis must be accomplished very precisely to avoid injury to adjacent structures. Bipolar coagulation is one of the more precise techniques, since theoretically, current flows only through tissue that is held between the tips of the forceps. Experiments were done in rats to confirm that bipolar coagulation can be used to control vessel branches without disturbing the parent vessel or adversely affecting an adjacent anastomosis. However, the importance of the characteristics of the bipolar generator require particular attention. The generator used in these experiments produces a continuous-sine-wave current to minimize voltage. In addition, the equipment was designed to sense impedance and to automatically shut down at the point of desiccation, thus avoiding sparking, charring, and adherence of tissue to the forceps.