Some herbs can interfere negatively with things like chemotherapy; that’s why the doctors recommend foregoing them during treatment. You don’t want to be doing something that is helping the cancer because it’s negating the treatment. My hubby had four cycles of chemo, the mass shrunk by about half, and he has surgery this Thursday. It’s hard to know what to do and not do sometimes but doctors should be willing to talk with you and explain things. I’ve found that they often don’t like when we question them but it’s important to know what your options are and have doctors who listen when you tell them what you’re feeling.