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Nature’s Virus Killers

It is the time of year when people around the country start contracting upper respiratory tract infections such as the common cold more readily. I have written about some of the more potent anti-viral herbs that I prescribe to patients when they become ill to quicken their recovery.


This plant is used medicinally as a prescription herb and food throughout China for thousands of year. It has become a favorite among western herbalists for its benefit to the immune system. Although traditional Chinese medicine does not distinguish between viruses and bacteria, herbs are prescribed based on sets of patterns and symptoms. Using the Chinese medicine model, Astragalus is used to strengthen the lung and spleen (the organ in Chinese medicine involved in digestion) meridians. It improves symptoms related to a spleen deficiency such as lack of appetite, fatigue, and diarrhea. For lung deficiency syndromes, it is indicated for frequent colds and shortness of breath. Astragalus is said to strengthen the protective qi, which many western practitioners equate to the immune system. It is also effective against bacterial infections. Many studies demonstrate the immune enhancing effects of Astragalus. Patients with viral myocarditis (viral infection of the heart) showed improvements in immune status when given Astragalus extract. Astragalus is also used as an adjunctive herb in the treatment of cancer and to reduce the side effects of chemotherapy drugs.


This antiviral herb is best known among the Chinese as ling zhi and among the Japanese as ling chih. Both cultures have used Reishi mushrooms for more than 4,000 years to treat chronic hepatitis, enlarged liver, high blood pressure, arthritis, insomnia, neurasthenia, bronchitis, asthma, and gastric ulcers. In the famous Chinese natural history book Ben Cao Gang Mu (1578), authors wrote that “continued use of ling zhi will lighten weight and increase longevity.” Professor Hiroshi Hikino, one of today’s premier authorities on Oriental herbs, classifies Reishi as one of the “most important elixirs in the Orient. ”Actually, there are six different types of Reishi mushrooms, all classified according to color. The red Reishi mushroom is considered to deliver the most potent medicinal benefits. Asian studies report that Reishi improves conditions among people with hepatitis and bronchitis. One study reported 60 to 90 percent improvement among 2,000 people with bronchitis within two weeks of taking Reishi. Throughout its long history of use, Reishi has never had any reports of toxicity or side effects on people.

Olive Leaf

Ancient Egyptians used olive leaf extract to mummify their pharaohs. 19th Century Britains relied on olive leaf extract to treat tropical diseases such as malaria. Today, scientists are still discovering more benefits of this botanical health restorer. This herb is an excellent source of phytochemicals that provide powerful antiviral, antiparasitic, antifungal and antibacterial properties. Researchers in the early 1900s were able to isolate a phenolic compound from olive leaves called oleuropein.  Scientists determined that oleuropein was the ingredient that kept trees disease-free and resistant against insects.  Olive leaf also contains flavonoids (including rutin flavonol, luteolin-7-glucoside flavone and hesperidin flavone) as well as elenolic acid. What does this mean? Well, these ingredients are mighty weapons against the common cold, the flu and other respiratory infections. In addition, individuals who take olive leaf extract regularly report increased energy levels. Although there is not much in the way of human studies with olive leaf, I have had many people report tremendous benefit with its use in viral infections like the common cold and flu.

Licorice Root

The most commonly used form of licorice root used in the Western world is glycyrrhiza glabra. In Chinese medicine, the most popular type is glycyrrhiza uralensis. Licorice root has been used therapeutically for thousands of years. It possesses immune-stimulating effects, antiviral, anti-inflammatory and anticancer properties. One of its main active constituents, glycyrrhizin, is 100 times sweeter than sucrose. The active constituents glycyrrhizin and glycyrrhetinic acid activate interferon by the immune system which has strong antiviral activity. Licorice root has also been shown to inhibit the growth of many viruses including herpes simplex type. Topical applications work well in reducing pain and healing time of both oral and genital herpes and can be bought commercially as a cream.


This shrubby tree with musk-scented wood has enjoyed a reputation as a medicinal herb since the days of Hippocrates, the father of medicine. In 17th Century Europe, elderberry was dubbed the “country medicine chest” because of its ability to fight viruses and bacteria. One legend tells of how the elderberry tree provided protection and warded off evil spirits. For centuries, people have picked its berries and made them into delicious wines, pies, and preserves. Modern scientific studies report that key active ingredients extracted from elderberry provide the first line of defense against a viral invasion, especially different flu strains. Somehow, these ingredients neutralize new viruses released from invaded cells and prevent them from replicating themselves. Research performed in Israel showed that the juice from the berries of elderberry stimulates the immune system and inhibits the influenza virus. Patients with the flu have reported significant improvements within 24 to 48 hours, in contrast to those who received placebos and too six days to recovery. Not only is elderberry a great preventive against the flu, it also partners well with echinacea in dealing with colds and respiratory infections. If you're dealing with seasonal respiratory issues, contact the Stengler Center for Integrative Medicine today!