Final answer:
Herbal substances can indeed affect a patient during surgery as they may interact with anesthesia and other medications, potentially leading to complications.
Step-by-step explanation:
Substances that can affect the client in surgery do include herbal substances. This is because herbal supplements can have a significant impact on the body's physiology and can interact with anesthesia and other medications used during surgical procedures. It is crucial for patients to inform their healthcare providers about any herbal supplements they are taking prior to surgery to prevent potential complications such as changes in heart rate, blood pressure, and bleeding risk.