Using Herbs and Essential Oils Safely

The essential oils of wormwood and tansy should not be used at all?these plants contain thujone, which can cause seizures. If you want to use the herbs, you must also be careful. The essential oils of wintergreen and thyme can irritate the skin, even when diluted.

Pennyroyal developed a bad reputation in 1978 when one unfortunate 18-year-old woman died after downing an entire ounce (two tablespoons!) of the essential oil while trying to discontinue a pregnancy. After that, the FDA declared that the essential oil and the herb itself must be labeled "for external use only." According to Norman Farnsworth, Ph.D., professor of pharmacology at the University of Illinois, Chicago, an ounce of pennyroyal essential oil equals roughly 75 gallons of the tea!

You should also avoid using any strong herbs or herbal derivatives during pregnancy. This includes goldenseal, barberry and Oregon grape root; laxatives such as senna and cascara sagrada; and coffee, kola nut and guarana, all of which contain caffeine. Also watch out for herbs that produce hormonal actions, don quai, fenugreek and red clover among them, and uterine stimulants such as aloe, fenugreek and rue.

If you are pregnant, you should also avoid large quantities of herbs with aspirin-like actions, such as willow and meadowsweet, because aspirin itself has been linked to birth defects. Chances are that this is not true of aspirin-like herbs, but you might as well play it safe. Black cohosh and blue cohosh are sometimes used during the last few weeks of pregnancy to prepare the uterus for child-birth, but if you are interested in using these herbs, I recommend that you find someone who is experienced in herbs to work with you.