It’s important to take herbs to prevent colds and flu if you tend to get sick often or are around others who have caught the latest bug. There are several effective herbs that help reduce the number of wintertime illnesses and the duration.
The immune system is the body’s defense against infection. Sometimes our immune system becomes weakened and we are more susceptible to illness. Scientific research supports the use of several herbs to help avoid colds and flu by boosting the immunity. They are called immune tonics.
Immune tonics work to strengthen and build the immune system. They not only help prevent illnesses, they play a key roll in overall good health and wellbeing. Herbal tonics can be taken safely for long periods of time. For best results, use one or more of these herbs to prevent colds and flu regularly. In addition, be sure to get enough rest, eat well and manage stress.
Herbs to Prevent Colds and Flu
Garlic – Allium sativum
Garlic has a long history as valuable medicine. It is a common cooking ingredient found in most well-stocked kitchens. Garlic can be purchased just about anywhere making it one of the most convenient medicines. While garlic has a number of important medicinal virtues, it is one of the best herbs for warding off colds and flu. It has both antibacterial and antiviral properties. This is due to numerous beneficial compounds. 
One compound in particular has attracted the most attention, allicin. When garlic is cut or crushed, the compound alliin comes into contact with the enzyme alliinase to create allicin. This takes about ten minutes and is volatile so it does not last long. Therefore, the best way to take garlic is raw, roughly ten minutes after cutting. Some find eating raw garlic disagreeable. If so, it can easily be pickled or aged for a more mild flavor. Eat one or two cloves a day.
Garlic is slightly blood thinning so do not take with pharmaceutical blood thinners and discontinue at least a week before any surgical procedure.
Shiitake Mushrooms – Lentinula edodes
While technically not plants, medicinal mushrooms are well-known by herbalists for boosting the immune system. Several different types of mushrooms have been used by Traditional Chinese Medicine as immune tonics for thousands of years. It is the polysaccharides that are most noted for antibiotic and antiviral properties. Mushrooms such as shiitake, reishi and cordyceps work deeply at the bone-marrow level where macrophages and immune cells are made.
Christopher Hobbs in his book Medicinal Mushrooms states, “Shiitake is used medicinally for any and all diseases involving depressed immune function, including … frequent flu and colds.” He also states that it “works through both humoral and cell-mediated immune mechanisms.”
Shiitakes are a favorite since they can be incorporated into food easily. You can purchase them fresh or dried from most well-stocked grocery stores. Put them in stir fries, soups, vegetable dishes, eggs and pastas.
Astragalus – Astragalus membranaceus
Astragalus is another herb with a long history of use in Traditional Chinese Medicine. Also similar to the medicinal mushrooms, the polysaccharides activate and strengthen the immune system. It is thought to produce both immune cells and immune compounds in the body. Dr. Andrew Weil states, “This is one of my favorite immune-boosting tonics. I recommend taking astragalus preventively through the flu season for its anti-viral effects.”
The part of the plant used is the root which when sliced and dried looks like a tongue depressor. It has a sweet taste and can be made into tea or tincture. One of the best ways to take astragalus for prevention is simmered in soups. Be sure to remove it before consuming since it is too woody to eat.
Elderberry – Sambucus nigra, Sambucus canadensis
Elderberry contains flavonoids that help keep you from contracting flu and respiratory viruses. It works by blocking viruses from entering cells and replicating. Elderberry contains a number of other immune boosting compounds as well as vitamins A and C.
One study from 2009 concluded, “The H1N1 inhibition activities of the elderberry flavonoids compare favorably to the known anti-influenza activities of … Tamiflu.” 
Elderberries grow in many places world-wide and are frequently harvested for medicine. Be sure to use the dark purple elderberries rather than the red berries. They can often be purchased frozen or dried as well. Make them into a tincture or a delicious elderberry syrup.
Echinacea – Echinacea purpurea
Echinacea’s ability to prevent or treat wintertime illness has been quite controversial. While many studies point to its efficacy, there are other studies that state otherwise. To get to the bottom of echinacea’s effectiveness, a meta-analysis was performed on the studies. It concluded, “Based on the analysis, the likelihood of experiencing a clinical cold was 55% higher with placebo than with Echinacea.” 
Echinacea also contains immune stimulating polysaccharides to naturally enhance the body’s resistance to infection. It increases immune compounds such as interferon and helps to keep pathogens at bay.
If taking Echinacea for prevention, take ½ teaspoon of tincture twice daily. This is for short-term prevention only. Do not take for longer than 8 weeks and do not use in place of building and nourishing a healthy immune system. If taking Echinacea once an illness hits, be sure to start taking the tincture frequently at the very first signs of the infection. This would be ½ teaspoon every two hours for the first 24 to 48 hours.
Feel free to leave any comments or questions below. If you would like to learn more about herbal medicine, check out the Home Herb School at www.homeherbschool.com
 Nantz MP, Rowe CA, Muller CE, Creasy RA, Stanilka JM, Percival SS (2012). Supplementation with aged garlic extract improves both NK and γδ-T cell function and reduces the severity of cold and flu symptoms: a randomized, double-blind, placebo-controlled nutrition intervention, Clinical Nutrition, doi: 10.1016/j.clnu.2011.11.019
 Roschek B Jr, Fink RC, McMichael MD, Li D, Alberte RS (2009). Elderberry flavonoids bind to and prevent H1N1 infection in vitro, Phytochemistry, doi: 10.1016/j.phytochem.2009.06.003
 Schoop R, Klein P, Suter A, Johnston SL (2006). Echinacea in the prevention of induced rhinovirus colds: a meta-analysis, Clinical Therapeutics, doi: 10.1016/j.clinthera.2006.02.001