Over thousands of years, indigenous cultures have used traditional herbal medicine to prevent and treat diseases, including respiratory ailments like colds and influenza. In the modern day, the bioactive compounds of medicinal plants have become primary points of research for drug therapies, but the plant remedies still hold promise when used as nature intended.
“While the plant kingdom continues to serve as an important source for chemical entities supporting drug discovery, the rich traditions of herbal medicine developed by trial and error on human subjects over thousands of years contain invaluable biomedical information just waiting to be uncovered using modern scientific approaches,” researchers wrote in Nature Plants in 2017.1
Now, with the COVID-19 pandemic, the use of traditional herbal medicine for the treatment of respiratory ailments has taken on renewed interest, and researchers from the Chinese Academy of Agricultural Sciences and China’s Hebei Agricultural University compiled some of the most useful herbs for the prevention and treatment of cold and flu, and potentially COVID-19, too.2
Top Expectorant Herbs for Cold and Flu
Expectorant herbs are useful for thinning and loosening mucus, helping to clear congestion. They’re often used for coughs and colds, as they may make breathing easier.
After conducting a literature survey on natural herbal medicines, particularly those from traditional Chinese and Persian medicine, the researchers suggested the following herbs had significant potential as expectorants for cold and flu:3
Tulsi — Tulsi, also known as holy basil, is an Ayurvedic herb with antibacterial, antiviral, antifungal, anti-inflammatory, analgestic, antioxidant and adaptogenic properties.4 A review in the Journal of Ayurveda and Integrative Medicine even called tulsi an “herb for all reasons,” noting that it’s effective against “a range of human and animal pathogens” with broad-spectrum antimicrobial activity. They even suggested it could be used as a hand sanitizer.5
Tulsi is also one of the herbs in Ayush Kwath, an Ayurvedic herbal formula recommended by the government of India to boost immunity and combat COVID-19.
“Ayush Kwath due to its immune-modulatory, antiviral, antioxidant, anti-inflammatory, anti-platelet, anti-atherosclerotic, hepato-protective, reno-protective properties; seems to be effective in immuno-regulation for controlling viral infections like COVID-19,” a team of researchers wrote in the Journal of Ayurveda and Integrative Medicine.6
Snake root — Used by North American Indians to treat snake bites, snake root, or Polygala senega, is also valued for its stimulant, expectorant properties and has traditionally been used to treat respiratory ailments.7
Licorice root — Licorice root contains liquiritin, a compound that helps prevent the rapid reproduction of SARS-CoV-2, the virus that causes COVID-19, as demonstrated in the lab.8 The compounds in licorice root have demonstrated antiviral and anti-inflammatory effects in the body and the ability to modulate the immune system.
A second compound in licorice root that has demonstrated an effect against SARS-CoV-1 is glycyrrhizin.9
Glycyrrhizin has traditionally been used in the treatment of coughs and viral respiratory tract infections in China, India and Greece, and animal studies suggest it reduces mortality from herpes encephalitis and influenza A pneumonia, while in vitro studies show it has “antiviral activity against HIV-1, SARS-related coronavirus, respiratory syncytial virus, arboviruses, vaccinia virus and vesicular stomatitis virus.”10
Clove — Cloves (Syzygium aromaticum or Eugenia cariophylata) are the aromatic flower buds collected from evergreen trees of the same name. Eugenol, a major volatile constituent of clove essential oil, has a range of pharmacological activities including antimicrobial, anti-inflammatory, analgesic, antioxidant and anticancer properties.11
One way to use clove as a respiratory aid is to make clove tea, which you can either drink or use as a steam inhalation. For a cold, you can add a couple of drops of clove essential oil to a mug of hot water, sweetened with raw honey or stevia if desired. Drink two to three glasses a day until your condition improves. You can also use clove oil for aromatherapy by diffusing it into the air.
Slippery elm root — The inner bark of the slippery elm tree is a slimy substance that, when mixed with water, creates mucilage, a sticky substance traditionally used for soothing a variety of ailments. In addition to being used for gastrointestinal problems like irritable bowel syndrome,12 slippery elm is beneficial for the throat and coughs, and has soothing effects on the tissue of the upper airway.13
Marshmallow root — This perennial herb has been valued for treating respiratory ailments since ancient times, and research suggests that, when added to an herbal cough syrup, it’s useful for alleviating cough associated with colds, bronchitis and respiratory tract diseases that involve the formation of mucus.14
Sage — Sage, in addition to having antimicrobial and anti-inflammatory properties, is a natural expectorant and useful to clear mucus and reduce coughs, and even calm a sore throat.15 Consider adding a drop of sage essential oil to a cup of tea or hot water the next time you have a cold.
Top Antiviral and Immunostimulant Herbs
In their review of the best herbal medicines for cold and flu, in addition to COVID-19, the researchers of the featured study also highlighted antiviral herbs and those that stimulate the immune system. While most medicinal plants have a variety of benefits with overlapping therapeutic properties, the following stood out in these categories. Important antiviral herbs included:
Thyme — Thyme (Thymus vulgaris), contains potent compounds like thymol, camphene, linalool, and carvacrol and has been used traditionally for respiratory issues. Modern research shows vaporized essential oils from thyme, among others, may “potentially useful in influenza therapy.”16
Venezuelan officials also announced they have had encouraging results treating COVID-19 patients with Carvativir, an oral solution made from extracts of thyme and oregano.17
Honeysuckle flowers — Honeysuckle (Lonicera japonica) is another plant with a long history of use for respiratory ailments.18 It contains chlorogenic acid, which one study found “inhibited influenza virus during the late stage of infectious cycle” and also effectively reduced inflammation in the lungs and reduced viral titers during the study.19
Andrographis — This adaptogenic and antiviral herb has been used in Traditional Chinese Medicine and Ayurveda to treat the common cold.20 In a systematic review of 33 randomized controlled trials with 7,175 patients, andrographis helped relieve the symptoms of acute upper respiratory tract infection and shortened the time for cough and sore throat as well.21
In another review of the literature, scholars found “strong evidence” that Andrographis was superior to a placebo in reducing the frequency and severity of coughs.22 A formulation known as Kan Jang that combines andrographis and Siberian ginseng has also been studied, with positive results, in the treatment of colds,23 upper respiratory tract infections,24 sinusitis25 and flu.26
Yarrow — This perennial herb contains many constituents with pharmacological activity. It’s traditionally been used for respiratory infections, colds and flu,27 and is sometimes combined with elder flower for this purpose.
Peppermint — Peppermint oil acts as an expectorant and decongestant, and may help clear your respiratory tract. Use peppermint essential oil as a cold rub on your chest or inhale it through a vaporizer to help clear nasal congestion and relieve cough and cold symptoms.
Calendula — Also known as marigolds, calendula has anti-inflammatory, antiviral and regenerative properties that are also stimulating for the immune system.28
The following herbs, in addition to marshmallow root and slippery elm, were also highlighted for their immunostimulant properties particularly for cold and flu:
Echinacea — In a study published in Integrative Cancer Therapies, echinacea was found to reduce the severity and duration of colds if it is administered right away once symptoms appear.29
Garlic — With both immune-boosting and antiviral effects, those who consumed garlic daily for three months had fewer colds than those who took a placebo.30
Ginseng — Another adaptogenic herb, older adults who took an extract of American ginseng had a 48% reduction in relative risk, and a 55% reduction in duration, of respiratory illness.31 This herb was also found to be “a safe and effective treatment for reducing the absolute risk of recurrent colds and the mean number of colds per person.”32
Isatis root — Isatis is a flowering plant used in TCM and Ayurveda, often in combination with other herbs. Teas and mouthwashes containing isatis, honeysuckle, mint and licorice root have also been successful at treating respiratory problems, including influenza.33
Usnea lichen — Usnea is a type of lichen that grows on trees and rocks around the world. It contains polysaccharides that may boost immune system activity, making it useful for colds and flu.34
Myrrh — Myrrh is a thorny tree or shrub that releases a resin from cracks in the bark. This resin has traditionally been used to treat colds and cough,35 and with known antiviral and immunomodulatory properties, researchers suggested myrrh mouthwash could be effective in combating COVID-19.36
Ginger — Ginger root has been used as a tonic to treat common ailments for centuries, and a number of studies have documented the antioxidant and immunomodulatory effects of this herbaceous perennial plant.37
Nature Is Full of Powerful Healers
Herbal medicine is a powerful arsenal in the prevention and treatment of respiratory ailments like colds, flu and COVID-19. In China, herbal treatment is recommended for children and adults with COVID-19,38 and interest in traditional remedies is growing in the U.S. as well.
Herbs are unique in that they contain multiple beneficial components that work synergistically to promote wellness. As noted in the featured study:39
“Some important chemical constituents of traditional herbs, which can be considered in the fight against COVID-19, are betulinic acid, coumaroyltyramine, cryptotanshinone, desmethoxyreserpine, dihomo-γ-linolenic acid, dihydrotanshinone I, kaempferol, lignan, moupinamide, N-cis-feruloyltyramine, quercetin, sugiol, and tanshinoneIIa.”
Because working with herbs can be complex, for best results consult with a knowledgeable natural health care practitioner who can guide you on the appropriate herbal solutions for your circumstances.