Understanding Herbal Actions

Long before scientists began to study how herbs work, traditional healers discovered herbal actions empirically. They used intuition and observed how animals use plants to heal themselves. They experimented, then verified and documented what they learned so that their knowledge could be passed along.

These hands-on healers — folk doctors and village healers, shamans, monks, and nuns, all serving their communities — are the ones to thank for many so-called scientific discoveries about herbs. The indigenous people of northeast Brazil, for example, have long used the jaborandi plant (Pilocarpus jaborandi) for medicinal purposes, including the promotion of salivation. Pilocarpine, a pharmaceutical medicine developed from this species, has been used worldwide to treat glaucoma and other conditions. Most recently, it was approved for the treatment of “dry mouth syndrome,” which can be a side effect of radiation therapy or certain health conditions. And while laboratory research shows that garlic (Allium sativum) has antimicrobial activity, traditional healers knew this through experience and have long used the herb to treat all kinds of infections, from colds and flu to infected skin wounds.


Feverfew (Tanacetum parthenium) is best known for helping prevent migraine headaches, but it has also been used to treat arthritis, dizziness, tinnitus, and painful menstruation.

One way to learn how to use medicinal herbs is to learn about their possible effects on the human body. Much like modern pharmaceuticals, herbs can have antispasmodic (muscle-relaxing), analgesic (pain-relieving), and anti-inflammatory effects. Other herbal actions are described with unique terms such as adaptogenic (helping the body defend against physical stress), alterative (slowly restoring efficient body function), and carminative (enhancing digestion).

Herbs appear to have what herb researchers call “affinities” to particular body systems; in other words, herbal actions are more pronounced in some parts of the body than others. Among demulcent (inflammation-relieving) herbs, corn silk (Zea mays) comforts the urinary tract, while marshmallow root (Althaea officinalis) soothes the digestive tract. Kava (Piper methysticum) is an antispasmodic that relaxes muscles all over the body, while wild cherry bark (Prunus serotina) acts primarily to relax respiratory muscles. Hawthorn (Crataegus laevigata) strengthens the heart and blood vessels, while raspberry leaf (Rubus idaeus) tones the tissue of the uterus.

In addition, even though an herb can be especially well known for a certain effect (and so is termed a “specific” for a particular condition), most herbs provide a combination of actions. German chamomile (Matricaria recutita), for example, is known as a specific for the treatment of stomach ulcers because it has an anti-inflammatory effect on the digestive tract. It also soothes frazzled nerves, relaxes tense muscles, alleviates indigestion, and is a valuable anti-inflammatory remedy for skin irritations. Feverfew (Tanacetum parthenium) is best known for helping prevent migraine headaches, but it has also been used to treat arthritis, dizziness, tinnitus, and painful menstruation or sluggish menstrual flow.

In other words, from a therapeutic perspective, herbs have both primary and secondary actions. By considering the primary and secondary actions of herbs, as well as their body-system affinities, an herbalist can choose an herbal treatment appropriate not only for relieving an acute problem, but also for improving chronic conditions or heading off future problems.

Catnip (Nepeta cataria), for instance, is an antispasmodic herb that also relieves indigestion and acts as a mild sedative, so it’s an excellent choice for someone who suffers from stress-related indigestion. And garlic (Allium sativum), which relieves infections and aids the circulatory system, could benefit someone who has bronchitis as well as a family history of heart disease.