Often conflated to refer to the same condition, “cold” and “flu” are really two distinct viral infections. A major difference between them is that a cold can be caused by a range of viruses, whereas “flu” refers specifically to infections involving one of three influenza viruses. Flu infections are often worse than colds and may require more aggressive treatment.

Average infection rates range from two to five per year for adults to six to 12 per year for children. Infection is usually the result of an infected person coughing or sneezing into the air or by an uninfected person touching an infected object or person, and then introducing the virus to their own body by touching their eyes, nose and/or mouth. Considering just the work and school days that are lost to infections of this type, the cost to human society is enormous.  

Cold and Flu vs. Allergies

Initially, it can be difficult to tell the difference between allergies and a cold or flu. Sneezing, sore eyes, runny nose and a headache can feel like a cold coming on. But, these symptoms will normally only last a few days with a respiratory infection. With allergies, these symptoms will often continue beyond a week.


Pollutants and Allergens: The human respiratory system is well-accustomed to exposure to foreign organisms, pollutants and allergens. Under normal conditions, these foreign invaders stick to the moist mucus layer that coats the respiratory lining, where the small hair-like structures called cilia sweep them up and out of the trachea. The mucus is then either swallowed and exposed to the highly acidic environment of the stomach or simply coughed up and expelled. 

Cold Temperature: While it seems reasonable that prolonged cold temperatures could weaken an individual’s resistance to cold and flu viruses, cold temperature itself does not increase the likelihood a person will become infected. Any correlation with colder temperatures appears to be due to the lower humidity drying the protective mucous membranes to the point where the mucus dries up, and the cilia are no longer able to effectively sweep viruses along the respiratory mucosa. If they become too dry as a result of this lower humidity, the mucous membranes can even crack, which further exposes the body to infection. Using a vaporizer or a humidifier during the dry winter months can help reduce susceptibility to respiratory infection by keeping the mucous membranes moist. Smoking can also damage the respiratory cilia and increase the risk of infection. People also tend to spend more time indoors with others during the winter months, increasing their exposure to viruses.

Stress: Research suggests that stress plays a role in weakened immunity and may even double the likelihood of infection. Prolonged stress is known to result in sustained high levels of the adrenal hormone cortisol, which may play a role in some aspects of reduced resistance. It’s also been hypothesized that the effects of stress are much broader and can disrupt cross-system communication between the nervous system, the endocrine/hormonal system and the immune system. 

Lack of Sleep: Getting more than six hours of sleep a night is essential for maintaining healthy psychological and physical resistance and immune function. 

Poor Dietary Habits: Poor eating habits can leave someone deficient in vitamins, minerals and other co-factors needed for a healthy immune response (e.g., a completely fat-free diet, a zinc-deficient diet, etc.), or they can be a burden to key physiological processes that keep us healthy (e.g., pizza or French fries that lead to liver congestion and inflammation). A well-balanced diet is integral to a healthy immune response.

Personal Hygiene: Washing your hands regularly and keeping them away from your eyes, nose and mouth are probably the most influential measures you can take to reduce your likelihood of an infection. 

System Hijack

Viruses hijack the body’s own cellular processes in order to enter our cells and replicate. To achieve this, they first bind to a mucous membrane, most typically in the nose, throat and lungs. The virus then prompts the cell to transport the virus to its interior, where the virus disassembles and produces more viral RNA (a genetic messenger). These newly manufactured viral proteins are then moved onto the surface of the infected cell, where they can migrate to other cells and repeat the process. The replicated virus may also be sneezed or coughed into the environment.

Conventional Treatment

There’s no cure for the common cold or flu. Most doctors today will simply advise patients to go home, get plenty of rest, drink lots of fluids and take anti-inflammatory medications. While antiviral drugs can be prescribed, their statistical effectiveness seems limited to reducing symptoms by only a few hours, which doesn’t outweigh the risks associated with them for a lot of people. 

Antibiotics cannot treat a viral infection, yet they are still being prescribed to cold and flu patients. Such overuse, when not warranted, is believed to only increase antibiotic resistance to future bacterial infections. 

An Herbal Strategy

So, what can be done about a cold or flu infection from an herbal perspective? A sound place to start usually includes supporting the immune response, managing symptoms and offering affected systems appropriate support. 

Immune System Support: The short-term strategy supports the non-specific immune response; the long-term one supports the adaptive or specific immune response.

Short-Term: Innate immunity refers to the non-specific branch of the immune response. The cells of non-specific immunity are the “first responders” of the body’s response to infection. They call other immune cells to the location, pass on suspected offenders to other immune cells for identification, and help clear dead cells and debris from the infected site. 

Echinacea root (Echinacea angustifolia) and andrographis (Andrographis paniculata) could be included in virtually any short-term immune formula. Echinacea has been shown to stimulate non-specific immune cells, like phagocytes. It also helps manage immune system compounds called cytokines, mostly responsible for a number of the key symptoms of colds and flu. Andrographis is bitter, and echinacea produces a distinct localized tingling sensation that can be quite strong; however, herbs can usually be added from other supportive categories to help improve their taste. Echinacea has a long-standing reputation as a blood purifier. Andrographis is a bitter, which gives it liver- and bile-stimulating activity. It’s liver-protective and somewhat anti-inflammatory.

Long-Term: A long-term immune strategy focuses on building resistance and enhancing the body’s ability to handle future exposure to infection. For the most part, long-term immune herbs should not be given during an acute infection. Rather, these herbs are taken between illnesses and are ideal for the person who “catches everything going around.” 

Mitigating your risk factors and promoting general health is one of the best places to start. Eating well, exercising, taking a good multivitamin, getting plenty of rest and reducing stress are all excellent first steps. On the herbal side of things, a lot can be done in the way of long-term support. The main categories of herbs that offer the most assistance here are immune tonics and adaptogens. Astragalus (Astragalus membranaceus) and reishi mushroom (Ganoderma lucidum) are outstanding immune tonics. Though not traditionally recognized as adaptogens, they enhance endurance and make excellent foundations for almost any long-term immune system strategy.

More traditional adaptogens are also of benefit here. They are the generalists of a long-term herbal strategy for immunity. The good news is that there are many adaptogens to choose from. My favorites are schizandra (Schizandra chinensis), eleuthero (Eleutherococcus senticosus) and rhodiola (Rhodiola rosea). Schizandra is excellent when there are liver concerns and/or when you want something that can be put into a water bottle and tastes okay. Rhodiola is often a good choice if the formula is for a woman or a girl, or where more mental stress is a factor; and, eleuthero is used when a good, reliable “middle of the road” adaptogen is needed. The various ginsengs (Panax spp.), American and Korean in particular, are also excellent for enhancing resistance and stamina.

Additional Support

While it might be easy to think of system support for a cold or flu infection as simply being ancillary to using more heroic immune herbs and symptom management, herbal medicines can really help the body’s own defensive processes where they need it. For this kind of support, an herbalist will often turn to diaphoretics and anticatarrhal, or expectorant, herbs.

Diaphoretics: These are warming herbs that promote sweating by dilating the peripheral blood vessels, allowing blood to come to the surface. They’re most often employed in fever management and to aid in the elimination of wastes through the skin. Ginger, cinnamon (Cinnamomum aromaticum), boneset (Eupatorium perfoliatum), yarrow (Achillea millefolium), black elderberry (Sambucus nigra), linden flowers (Tilia cordata) and prickly ash (Xanthoxylum americanum) are all popular diaphoretics. They can be combined, and most are best consumed as hot tea or as tinctures. 

Anticatarrhal Herbs: These herbs lend support to the mucous membranes of the upper respiratory system. They are often astringent and, as such, have a drying or “puckering” effect on the mucous membranes. Like a dry wine, much of this action is due to the tannins they contain. Anticatarrhals specifically help clear excessive mucus, which can cause the respiratory lining to become “boggy” and congested during infection. Eyebright (Euphrasia officinalis), bayberry (Myrica cerifera), goldenseal (Hydrastis canadensis) and black elderberry are reliable anticatarrhal herbs. Eyebright is more specifically used for the mucosa lining from the throat on up; goldenseal helps tonify the mucosal lining throughout the body. 

Expectorants: This category of herbs can help a cough become more productive by increasing watery secretion across the mucous membranes, thinning the thick mucus that can accumulate. Recommended expectorants include lungwort (Pulmonaria spp.), lobelia (Lobelia inflata), grindelia (Grindelia spp.), ginger, thyme (Thymus vulgaris), garlic (Allium sativum), eucalyptus oil (Eucalyptus globulus) in 1 to 3 drop doses, violets (Viola tricolor) and licorice.  

Demulcents: When a cough is dry and irritated, demulcents are used to help soothe the irritated respiratory tissue. Slippery elm (Ulmus fulva), coltsfoot (Tussilago farfara) and marshmallow (Althea officinalis) are demulcents that are worth knowing. When it comes to slippery elm and marshmallow, it is best to prepare these with hot water as a tea and allow them to cool until the water thickens with the mucilaginous (slimy) compounds. 

About the Author: Shayne Foley has been a professional Herbal Educator for 20 years, a subject expert on U.S. and Canadian TV and radio and a visiting lecturer at herbal and naturopathic medical schools across North America.

This article was originally published in the HERBAL REMEDIES™ #90 issue. To subscribe, click here.

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