Herbal medication and surgery

Herbal medications taking before surgery may cause bleeding complications and adversely interacting with anesthetic agents.    I copied a few more commonly usage here and not intended to be completely inclusive from Uptodate: 

• Garlic may increase bleeding risk and should be discontinued at least seven days prior to surgery.
• Ginkgo may increase bleeding risk and should be discontinued at least 36 hours prior to surgery.
• Ginseng lowers blood sugar and may increase bleeding risk and should be discontinued at least seven days prior to surgery.
• Kava may increase the sedative effect of anesthetics and should be discontinued at least 24 hours prior to surgery. An association between kava use and fatal liver toxicity has been reported.
  
• St. John's wort may diminish the effects of several drugs by induction of cytochrome p450 enzymes and should be discontinued at least five days prior to surgery.
• Valerian may increase the sedative effect of anesthetics and is associated with benzodiazepine-like withdrawal. There are no data on preoperative discontinuation. Ideally it is tapered weeks before surgery; if not, withdrawal is treated with benzodiazepines.
• Echinacea is associated with allergic reactions and immune stimulation. There are no data on preoperative discontinuation.
• Ephedra (ma huang) may increase the risk of heart attack and stroke and should be discontinued at least 24 hours prior to surgery.

In general, if you take any herbal medications, please let your doctor and nurses know.

Reference:
Uptodate. Perioperative medication management.  2012.