Why is it important to assess the patient for use of herbal products prior to surgery?

QUESTION 17:
Chapter 17, Preoperative Nursing Management
The nurse in a gynecology clinic is completing preoperative teaching for a patient scheduled for an abdominal hysterectomy next week. The patient states that she is currently taking 325 mg of aspirin daily for chronic joint pain, along with a multivitamin. The patient has type 2 diabetes; she closely monitors her blood glucose levels. Currently, she is taking an oral hypoglycemic agent. The nurse advises her to ask the anesthesiologist whether she should take this medication the morning of surgery. (Learning Objectives 2 and 4). Nursing Questions & Answers .
a. The nurse instructs the patient to stop taking the aspirin. What is the rationale for this action?
b. Why is it important to assess the patient for use of herbal products prior to surgery?
c.       The patient asks how surgery could affect her blood glucose; how should the nurse respond?