Supplement interaction with Chemo

Alright, finally found a more useful site from the Memorial Sloan-Kettering Cancer Center. First, let me copy a couple paragraphs for you:

"Can I use herbs or supplements safely during chemotherapy?Most herbs and dietary supplements have not been studied together with chemotherapy drugs and their interactions remain unclear. Many oncologists advise their patients to avoid these products during chemotherapy.
How do herbs interact with chemotherapy drugs?Herbs can interact with chemotherapy drugs through different mechanisms. Some herbs can interfere with the metabolism of the drugs, making them less effective. Other herbs may potentiate the adverse effects, such as bleeding, of chemotherapy drugs.
Do botanicals interfere with the metabolism of drugs?Yes, many botanicals interfere with the way a drug is processed in the body: Increased metabolism of a drug reduces its concentration in the blood and may reduce its effectiveness; decreased metabolism of a drug increases its concentration in the blood and can lead to toxicity or increased side effects.
How do I know if an herb or a vitamin can interact with chemotherapy drugs or other prescription drugs? Talk to your physician or pharmacist before taking dietary supplements."

 But then that being said, you can search their database, and each drug information sheet they provide has a Herb-drug Interaction statement. For example:
 "Herb-Drug Interactions
Supplement Interactions: High doses of selenium may decrease vitamin C absorption."