The Scientific Evidence on Herbs

The Scientific Evidence on Herbs

Clinical and laboratory studies of herbs have generated scientific evidence that herbs can effectively treat many diseases, says Varro E. Tyler, Ph.D., professor of pharmacognosy (the study of drugs from natural sources) at Purdue University in West Lafayette, Indiana.

The following herbs have been subject to the most scrutiny in European, Asian and North American studies. Dr. Tyler says that these nine herbs stand up to the highest clinical standards.

Chamomile. In the United States, chamomile is generally used as a tea, but Europeans use chamomile extracts, ointments and tinctures as well to treat a range of health problems, from indigestion to skin rashes. Chamomile tea, a gentle relaxant, makes an excellent bedtime drink. Scientific studies support chamomile's antispasmodic, anti-infective and anti-inflammatory uses.

Echinacea. Native American healers used this plant as a remedy for snakebites and skin wounds. Research shows that echinacea stimulates the immune system, helping the body defend itself against bacterial and viral infections.

Feverfew. In the 1980s, several British studies proclaimed feverfew's ability to reduce the severity and frequency of migraine headaches. Scientists believe that parthenolide, one of the active ingredients of feverfew, inhibits the release of serotonin and prostaglandin, hormones that may trigger migraines.

Garlic. Ancient Egyptians were serious garlic fans. They fed the odoriferous bulb to their slaves to keep them healthy. Now research shows that garlic can lower blood pressure and blood cholesterol levels and may even help heart attack survivors live longer. The National Cancer Institute in Rockville, Maryland, is studying garlic's tumor-fighting properties. On a more mundane level, garlic relieves gas and aids digestion.

Ginkgo. Research shows that ginkgo is particularly useful for treating problems caused by decreased blood flow to the brain. Elderly people who suffer from memory loss caused by circulatory problems may find that mental clarity increases when they take ginkgo. Studies also suggest that by improving circulation throughout the body, ginkgo can help prevent blood clots and mood swings accompanied by anxiety and can relieve the symptoms of tinnitus (ringing in the ears), asthma, phlebitis (inflammation of a vein) and vertigo.

Lemon balm. Studies show that this herb works well to calm nerves and to protect the body from bacterial infection. Europeans use lemon balm to treat cold sores caused by the herpes simplex virus. Preliminary tests suggest a cream containing lemon balm extract helps herpes lesions heal faster and extends the period between outbreaks of herpes.

Milk thistle. Animal and human trials show that this herb is a promising supplemental treatment for liver conditions, including hepatitis and cirrhosis. Milk thistle contains a mixture of flavonoid derivatives called silymarin that works directly on liver cells.

Saint-John's-wort. Traditionally used as a muscle relaxant to relieve menstrual problems, as a mild tranquilizer and as a treatment for depression and insomnia, Saint-John's-wort now also shows promise as a treatment for nervousness and anxiety. Active compounds in the herb appear to function as MAO (monoamine oxidase) inhibitors. An excess of MAO is a possible cause of depression.

Valerian. Studies show that this herb is a safe, effective alternative to prescription sleeping pills and tranquilizers. Scientists aren't exactly sure how or why it works, but valerian seems to depress central nervous system activity.