Log in »

Herbal Remedies and Cancer Treatment

One week before you have surgery or start chemotherapy or radiation therapy, you must stop taking any herbal or botanical home remedies or other dietary supplements because they can:

  • Interact with other drugs
  • Increase or lower blood pressure
  • Thin the blood and increase the risk of bleeding
  • Make radiation therapy less effective
  • Lower the effects of medications that suppress the immune system
  • Increase the effects of sedation or anesthesia

Common Herbs and Their Effects


  • Can cause an allergic reaction such as a rash or difficulty breathing
  • Can lower the effect of drugs used to suppress the immune system


  • Can lower blood pressure, fat, and cholesterol levels
  • Can prevent platelets (the blood cells that help stop bleeding) from sticking together, which increases the risk of bleeding

Gingko (also known as gingko biloba)

  • Can change how platelets function, which can increase the risk of bleeding


  • Can act as a stimulant, which can decrease the effects of anesthesia or sedation
  • Can interfere with platelet function, which can increase the risk of bleeding
  • Can lower blood glucose (sugar) level


  • Can reduce the antitumor action of chemotherapy drugs

St. John's Wort

  • Can interact with medications given during surgery
  • Can make the skin more sensitive to laser treatment


  • Can have a sedative effect, which can increase the effects of anesthesia or sedation

Herbal formulas

  • Many herbal formulas contain different herbs. We don't know their side effects. You must also stop taking these products 1 week before and during treatment

For more information about herbs and botanicals, visit the About Herbs, Botanicals & Other Products website at mskcc.org/aboutherbs.

You can also download the Memorial Sloan Kettering About Herbs app from the Apple App Store at itunes.apple.com/us/app/about-herbs/id554267162?mt=8.

This information does not cover all possible side effects. Please share any questions or concerns with your doctor or nurse.