Safe in Moderation
Herbalists have always known that some herbs need to be used more carefully than others. And some plants are downright poisonous. With a few herbs, however, there is a fine line between toxic and medicinal. That line is often determined by the dose.Most of the herbs suggested in this book are safe even if you take them in much larger quantities than suggested, but there are a few that must be used in moderation—or side effects may occur. When a certain herb has potential side effects, I have noted it in the text. This possibility should not, however, scare you away from using the herb—since herbal side effects are generally much less significant than pharmaceutical side effects. Even the Food and Drug Administration (or FDA; the government agency that regulates the sale of drugs in the United States) which takes a very conservative stance regarding herbs, has sanctioned the moderate use of many of the herbs mentioned in this book.
One common herb that can have side effects is licorice. We generally think of this herb as being safe—most of us associate it with candy—but taking large quantities can lead to sodium retention and potassium loss, which in turn can cause water retention, high blood pressure, headaches, shortness of breath and sometimes even heart problems. Experts writing in the Journal of the American Medical Association described one licorice lover who ate so much candy (two to four ounces a day for seven years) that he landed in the hospital with weakness and hormonal imbalances.
Just chewing and swallowing licorice-flavored tobacco hospitalized another fellow. As a result, licorice is not recommended in any form if you have high blood pressure or kidney disease or if you are pregnant. If you fit into any of these categories, you should be careful even with drugstore laxatives that contain licorice—most use highly concentrated extracts.
Other herbs that can raise blood pressure when taken in large amounts are ephedra, angelica, black cohosh (which also causes dizziness and irritates the nerves) and ginseng, according to some reports. ephedra and the caffeine-rich plants coffee, guarana, maté and kola nut stimulate the adrenal glands and can make you nervous, cause your heart to race and make it hard for you to sleep. Chances are that if caffeine were a new drug today, the FDA would approve it for prescription use only. Caffeine and derivatives of ephedra are added to diet and energy formulas that speed up your metabolism in an unhealthy way. These stimulants should be used sparingly or—even better—not at all. Several deaths have been linked to misuse of ephedra, so it's best to use this herb under medical supervision.
Other herbs that affect the adrenal glands include gentian and vervain. Gentian can make your body more sensitive to the adrenal hormone adrenaline. It is safe for most people to use, but in Germany people with high blood pressure are discouraged from taking it. Vervain has quite the opposite action, slightly depressing the heart rate, at least in animals, and constricting the bronchials. You should avoid it if you have asthma. To be on the safe side, if you have high blood pressure or a heart condition, do not use any of these herbs without professional advice.
There are also a few herbs that can foster digestive problems. Large quantities of hydrangea root or of extremely bitter herbs such as gentian and quassia, for instance, can cause nausea and vomiting. Generally speaking, if you become queasy after taking a particular herb, you are probably taking too much of it. (Remember, if you're sensitive to the herb, what's fine for someone else may be too much for you.)
Other herbs may impair your body's assimilation of vital nutrients. No one is sure, but some herbalists think that long-term use of garlic, goldenseal and, to some degree, barberry and Oregon grape root eventually depletes your intestinal flora and thus reduces the amount of nutrients you assimilate, especially B-complex vitamins. Taking large quantities of horsetail can create a deficiency of vitamin B1. When it comes to horsetail, you should use only the young plants, since older plants develop a toxic compound.
Long-term use of an irritant-type laxative herb such as cascara sagrada or senna causes potassium loss and electrolyte imbalance, which can irritate an existing bowel problem. (Electrolytes are important minerals such as sodium, magnesium and potassium.) One woman developed hepatitis after a month of taking sennoside B, an active compound isolated from senna, but it turned out that she was taking ten times the recommended maximum dose!