A 72-year-old woman underwent surgery for a distal radius fracture with lower jaw fracture under general anesthesia. Preoperative laboratory data showed hypokalemia (3.1 mEq · l(-1)), hypertension, and leg edema. The suspected cause of all of these symptoms was the licorice component of the multiple herbal medicines which she was taking. In addition, the ephedra and aconite tuber components of the Maobushisaishinto were suspected to be contributing to the hypertension. She was therefore taken off all of her herbal medicines. The patient underwent regular blood tests and her potassium levels were replenished perioperatively. Hypokalemia was alleviated within the few days following surgery. Given the identity of the crude contents of the multiple herbal medicines in addition to the postoperative plasma renin activity and aldosterone, pseudoaldosteronism was suspected. When administering multiple herbal medicines, knowledge of the precise contents is critical. Clarification of the doses of licorice and ephedra capable of inducing hypokalemia and hypertension would also be helpful.