An estimated 15 million people - and 22 percent of surgical patients - take herbal medications in one preparation or another, including single-herb dietary supplements, diet pills, muscle builders and so-called power drinks. Most times, you won't even know it. About seven patients in 10 fail to volunteer the use of herbals to the person taking their pre-op history. This a problem because many of these preparations can have consequences during surgery. Let's look at the eight most commonly used single-herb preparations. Unmanaged, each can present surgical concerns.

1 Echinacea.
Echinacea is a bitter herb from the daisy family. It has antibiotic, antiviral and anti-inflammatory properties and is used in many remedies to treat cold, flu or infection. It's marketed as a way to "rev up" the immune system. Long-term echinacea use (more than eight weeks) has been associated with immunosuppression. There's also the potential for hepatoxicity. Some patients may develop allergic reactions, so be on the lookout for atopic and asthmatic patients and those with allergic rhinitis. Instruct patients to stop taking echinacea at once in preparation for their surgery. If the patient fails to do so, the case may have to be postponed.

2 Ephedra (ma huang).
This drug, used in both Chinese medicine and in western countries, has attracted much attention in the news lately, so it's more likely now that patients will be aware of its potential dangers than in the recent past. The FDA recently banned the drug, but you should still query patients about its use. People use ephedra to promote weight loss, increase energy levels, and treat asthma and bronchitis. Ephedra and anesthesia can be a deadly mix. Ephedra increases blood pressure and heart rate; it indirectly releases endogenous catecholamines and directly affects alpha and beta receptors. It depletes the body's catecholamines and may contribute to perioperative instability.

The herb can cause myocarditis or cardiomyopathy vasoconstriction or vasospasm (tantamount to myocardial infarction or cerebral stroke). Ephedra can also react in combination with other drugs. For example, when combined with halothane, the patient may experience ventricular arrhythmia. The good news about ephedra, anesthesia-wise, is that patients are safe if its use is stopped at least 24 hours before surgery.

3 Garlic.
Used as a remedy for thousands of years, garlic lowers serum lipids and cholesterol, and affects the risk of developing atherosclerotic heart disease by reducing blood pressure and thrombus formation. Garlic's risks are entirely dose-dependent. There's no need for alarm if your patient merely eats garlic-heavy foods. Be aware of patients who add garlic supplements to their diet. Intraoperatively, garlic may cause increased bleeding (one of its properties is platelet inhibition) and potentiate anti-clotting medications such as warfarin (Coumadin). Instruct patients to stop taking garlic supplements seven days before surgery.

4 Gingko biloba.
The leaf of gingko biloba has many medicinal properties. It's used for a variety of indications, including cognitive disorders, peripheral vascular disease, vertigo and erectile dysfunction. Gingko inhibits platelet function and may increase bleeding during surgery. Patients should stop using gingko at least 36 hours pre-op.

5 Ginseng.
A staple of Chinese medicine, ginseng increases the body's energy, protects against stress and restores homeostasis. It's found in many preparations, including many popular teas. Ginseng may decrease blood glucose; hypoglycemia can be a problem intraoperatively with any NPO patient. Patients with Type II diabetes are at particular risk. Ginseng use may also lengthen cases by prolonging coagulation time. Lastly, be aware that ginseng may interact with other drugs, including insulin, anticoagulation drugs and MAO inhibitors. Instruct patients to stop its use at least seven days before surgery.

6 Kava.
Kava, which comes from the root of the pepper plant, is an anxiolytic and sedative herb. People use it mainly to treat anxiety. Its half life is nine hours. Heavy use is often characterized by scaly skin eruptions. Intraoperatively, kava potentiates benzodiazepines and barbiturates. Kava may interact with diazepam (Valium), alprazolam (Xanax) and other benzodiazepines. Patients should stop taking kava at least 24 hours before surgery.

7 St. John's Wort.
This herb is popular for treating mild or moderate depression, but it's problematic from a perioperative standpoint because it increases the metabolism of other drugs, increases liver activity and has anticoagulation properties. St. John's Wort is an especially bad drug to have in effect during transplanting. It's important for patients to stop taking it at least five days pre-operatively.

8 Valerian.
Valerian is a sedative contained in all herbal sleep aids. Long-term users often experience acute withdrawal symptoms when stopping its use. Even less-dependent users may experience withdrawal. The drug's properties are much like Valium's and affect the GABA receptors. Continued use increases barbiturate sleeping time, and valerian may interact with midazolam (Versed) anesthesia. If possible, patients need to stop taking herbal sleep remedies several weeks before surgery.

Prompt your patients
If you don't prompt patients about specific herbal preparations when you ask about the medications they take, you probably won't discover they use herbals. Many patients believe these medications are completely safe and don't even regard them as drugs.

While herbal use doesn't necessarily contraindicate anesthesia, these medications need to be controlled and, if possible, stopped before surgery. Find out which herbs patients take, for how long and at what doses. Educate them about the risks and instruct them to stop their use before surgery as indicated. This can be done during pre-op phone calls.