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Licorice
Not to be confused with the candy of the same name (though its sweet taste does originally come from the same source), licorice root is a perennial herb that’s been used for thousands of years for its variety of powerful healing properties. With a taste that can be as much as 50 times sweeter than sugar, its genus name, Glycyrrhiza, stems from ancient Greek, and literally means “sweet root”.
Native to the Mediterranean, Egypt and Asia, and one of the most widely used herbs in Chinese Medicine, licorice has traditionally been used as a remedy for upper respiratory complaints such as coughs, bronchitis and cattarrhs (a condition in which excess mucus is produced in the nose and throat). This is because it acts as an “expectorant”, meaning it helps to loosen and expel phlegm, easing congestion and coughs.
In addition to its effects on the upper respiratory tract, licorice is also commonly used to reduce stomach inflammation and to heal gastric ulcers. Research is ongoing into its effects on the immune system, its antiviral properties, and its ability to support the adrenal glands.
Active costituents
Triterpene saponins (glycyrrhizin, glycyrrhizic & glycyrrhetinic acid), flavonoids, iso-flavonoids, phytosterols, polysaccharides (glucans), coumarins, amino acids, lignans.
Cautions and warnings
Consult a health care practitioner for use beyond 4-6 weeks.
Consult a health care practitioner prior to use if you are pregnant or if you have a liver disorder.
Consult a health care practitioner if symptoms persist or worsen.
Contradictions
Do not use if you have hypokalemia, high blood pressure, or a kidney or cardiovascular disorder.
Do not use if you are taking thiazide diuretics, cardiac glycosides, corticosteroids, stimulant laxatives or other medications, which may aggravate electrolyte imbalance.
AVAILABLE RESEARCH
Upper respiratory tract
In this review, licorice is shown to work as effectively as codeine in the throat, decreasing irritations and acting as a helpful remedy for coughs, by facilitating the movement of mucus from the respiratory tract.
The results of this study, which examined mice with sulphur dioxide gas-induced coughs, concludes that ethanol extract of licorice exerts a significant antitussive effect (in experimentally induced cough reflex in mice), comparable to the standard drug codeine sulphate.
This review analyzes the benefits of herbal expectorants versus conventional opiod anti-tussives, which are primarily used to suppress coughs. Considering the role of coughs is to “clear the respiratory passages of foreign material and excess secretions”, the review points out the potential dangers of indiscriminately suppressing coughs with conventional cough medicine.
In a study on the effects of natural substitutes for synthetic antitussives, licorice extracts showed the ability to reduce citric acid-induced coughs in guinea pigs after oral administration in a dose of 50mg/kg. Among various herbs examined in the study, the strongest antitussive effect (81%) was found after application of the extract from licorice.
ADDITIONAL RESEARCH
There is ongoing research on the effects of licorice as it relates to the following health concerns:
Gastric ulcers
In this study, licorice was evaluated for its antiulcerogenic activity in mice. It was concluded that licorice showed antiulcer activity against indomethacin (a nonsteroidal anti-inflammatory drug)-induced gastric lesions dose dependently. The extract effectively inhibited formation of gastric lesions induced by ethanol, and was more potent than omeprazole (a medication used in the treatment of gastroesophageal reflux disease and peptic ulcer disease).
In this study on mice, similar conclusions were drawn, indicating that licorice root, given orally once daily to mice for seven days significantly protected the animal, and healed ulcers after seven days of treatment.
Anti-viral
This review describes the potential anti-viral effects of triterpenoids, one of the mainly active components of licorice, on viruses such as herpes virus, HIV, hepatitis virus, SARS coronavirus and influenza virus.
This review confirms that the licorice derived compound glycyrrhizin and its derivatives reduced hepatocellular damage in chronic hepatitis B and C, as concluded in various randomized control trials. In hepatitis C virus-induced cirrhosis the risk of hepatocellular carcinoma was also reduced. Animal studies demonstrated a reduction of mortality and viral activity in herpes simplex virus encephalitis and influenza A virus pneumonia. And in vitro studies revealed antiviral activity against HIV-1, SARS related coronavirus, respiratory syncytial virus, arboviruses, vaccinia virus and vesicular stomatitis virus.
Adrenal support
This study found that licorice and glycyrrhetinic acid increase DHEA and deoxycorticosterone levels (hormones needed to balance cortisol levels in the body) in vivo and in vitro by inhibiting adrenal SULT2A1 activity.
In this review from the Point Institute of Nutraceutical Research, natural therapeutic options for chronic stress were examined. It was concluded that when taken in smaller targeted doses, licorice root extract can be used to balance cortisol (stress hormone secreted in the adrenal glands) levels.
AVAILABLE RESEARCH ON CONTRAINDICATIONS
According to the National Centre for Complementary and Integrative Health, when taken in large amounts and with long-term use, licorice root can cause high blood pressure and low potassium levels, which could lead to heart and muscle problems. Some side effects are thought to be due to a chemical called glycyrrhizic acid.
NCCIH. "Licorice Root." (2016).
This article points out that some animal studies have shown licorice decreases the metabolism rate of warfarin, a blood-thinning medication, and it is not advisable to take licorice when on similar medication, or while taking diuretics.