Herbs For Seasonal Influenza

Flu usually refers to viral infections of the upper respiratory tract that are common and usually seasonal. Flu can also refer to seasonal, infectious gastrointestinal upset but this chapter focuses on respiratory influenza. Influenza is technically caused by one of three types of influenza viruses (A, B, or C), but many other viruses cause various flu-like syndromes. The viruses spread between people by airborne respiratory droplets, commonly in the late fall and winter. Recently it has been shown that cool temperatures in the autumn and winter stabilize and protect viruses for longer, thus enhancing transmission. Symptoms include runny nose, sore throat, nonproductive cough, fever, headache, muscle ache, and fatigue. In simple cases, the acute symptoms lessen within five days. Cough and fatigue, however, can persist. Viral pneumonia and secondary bacterial infections can be complications of flu; so ongoing fatigue and lung involvement are a red flag calling for medical evaluation, especially in the more vulnerable groups: young children, seniors, diabetics, the immune compromised (HIV, hepatitis, mononucleosis, etc.) and overworked, fatigued adults.

Influenza A is clinically the most important strain and its infection is characterized by fever and chills, often with cough, sore throat, headache, and myalgia. The best predictors of a laboratory confirmed diagnosis of influenza A are cough and fever. Other symptoms and complications may occur such as otitis media, conjunctivitis, and more severe respiratory tract symptoms. The most severe complication is viral pneumonia that can develop rapidly. Some patients also are at risk for developing secondary bacterial infections. The magnitude of viral replication, fever, respiratory and systemic symptoms directly correlate with levels of IL-6 and TNF-alpha in upper respiratory secretions. In volunteers treated with antiviral drugs, the reduction of viral replication was associated with a reduction in the production of these cytokines along with improved symptoms indicating that moderating these cytokines is beneficial.

Plant medicines offer a unique preventive and therapeutic approach. Herbs are often able to support physiological function in the human body so as to “boost” the body’s own immune response. Because they are not isolated molecules (but a mix of multiple molecular structures in a complex soup of active and inert ingredients) their antibacterial and antiviral actions are not particularly susceptible to the development of microbial resistance, drug-resistant bacterial strains may be more effectively treated with select herbal remedies.

Preventive Botanical Medicines During Flu Season

Treating Early Symptoms

Diaphoretic (also known as sudorific) herbs are a traditional flu treatment in the very early stages of influenza, such as a scratchy throat or slight cough during flu season. These herbs gently raise the body temperature and induce sweating, which appears to have a beneficial effect on the immune system. Diaphoretic herbs have been shown to promote sweating when given cold or given hot, although the hot infusions were the most effective. Traditional herbal diaphoretics of Europe and North America include German chamomile (Matricaria recutita) or Roman chamomilee (Chamaemelum nobilis) flower tea, brittlebush or incienso (Encelia farinosa) herb, anil de muerto (Verbesina encelioides) herb, yarrow (Achillea millefolium) flowering tops, and elder (Sambucus nigra) flower tea. Chamomile tea can also be inhaled as a steam, and elder flowers can be used as a bath. These remedies are particularly useful in infants and children as they are palatable and simple. Patients who already have very high fevers generally do not need diaphoretics.

Mucilaginous (demulcent) plants can soothe the mucosal surfaces of the throat, bronchi, and sinuses as well as reduce inflammation and irritation. Marsh mallow (Althaea officinalis) root, which is 5-35% mucilage when dried, is an excellent example. To extract the plant’s mucilage in a palatable form, a cold infusion (not a hot one) is prepared by pouring 8oz of cool distilled or spring water over approximately 8g of finely chopped marsh mallow root, and allowing it to steep, covered, at room temperature for 30 minutes with frequent stirring — four to eight hours with less frequent stirring. The cold infusion is then strained and sipped in 1-2 oz doses throughout the day to soothe an irritable cough or scratchy throat. A fresh batch is prepared daily, to protect against bacteria growing in the rich medium. Marsh mallow syrup is another typical preparation of this herb and is taken in teaspoon doses throughout the day during acute flu and cough symptoms. Other demulcent herbs to consider preparing as cold infusions for patients with influenza include elecampane (Inula helenium) and globemallow (Sphaeralcea spp.).

Antimicrobial Plants And Immunomodulators


Herbal medicines can play a useful role in treatment of patients with seasonal influenza infection. It is necessary for the clinician to choose the appropriate herbal remedies and not get caught in the trap of mindlessly prescribing the same treatments to every patient as though they were all identical. Rest and ample intake of water will generally serve all patients, but individualized herbal prescriptions chosen from those herbs discussed above will yield the best results. Patients should not expect perfect protection or an absolute cessation of symptoms, but instead reduced risk, symptom reduction, and quicker recovery than otherwise. The goal is to use herbs to provide a balance of improved health with minimal adverse effects.

Dr. Mitchell’s Knockout Antiviral Tea

The late Dr. William Mitchell, naturopathic physician and a cofounder of Bastyr University in Kenmore, Washington, recommended a flu tea discussed below. This is a diaphoretic, antimicrobial, astringent, demulcent tea to be taken three times daily or more.

Cinnamon bark sticks (Cinnamomum spp.), 2-3

Ginger root slices (Zingiber officinale), 4-5

Cardamon seeds (Elletaria cardamomum), 1 tbsp (optional)

Add the above ingredients to 4 cups of water or more. Bring to a boil, then simmer for 20 minutes, covered. Remove from heat.

Add the juice of half of a fresh-squeezed lemon. Add honey to taste.

Drink 1 cup three times a day for a maximum of seven days during a bout of flu.

A German Diaphoretic Tea

Elder flowers (Sambucus nigra), 1 tsp

Lime flowers (Tilia cordata), 1 tsp

German chamomile flowers (Matricaria recutita), 1 tsp

Add the above ingredients to 1 pint of boiling water. Remove from heat. Cover and allow to steep 10 minutes. Drink immediately.

Drink 1 cup three to five times a day for up to 10 days during a bout of flu.