The Traditional Use and Scientific Properties of Liquorice
Liquorice, also known by its botanical name Glycyrrhiza glabra, is an ancient herb with a deep-rooted history in various traditional medicine practices, including Chinese herbal medicine and Ayurveda. The root of the plant is valued for its sweet taste, which comes from the compound glycyrrhizin, a substance significantly sweeter than sugar. This compound and other active ingredients, including flavonoids and saponins, are responsible for its medicinal properties.
How Liquorice Works for Coughs
Liquorice root is often included in remedies for coughs and respiratory infections due to its multifaceted actions within the body:
- Demulcent Action: Glycyrrhizin acts as a demulcent, forming a protective, soothing layer over irritated mucous membranes in the throat. This action can provide instant relief for a sore throat or dry, hacking cough. Chewing on a small piece of the root is a traditional way to leverage this effect.
- Expectorant Properties: The saponins in liquorice root help to thin and loosen phlegm, making it easier to cough up and expel from the respiratory tract. This makes it particularly effective for productive or wet coughs by helping to clear congestion from the airways.
- Anti-inflammatory Effects: Compounds like glycyrrhizin and other flavonoids exhibit powerful anti-inflammatory effects. By reducing inflammation in the airways, liquorice can help alleviate the underlying irritation that contributes to coughing.
- Antiviral Activity: Studies have shown that glycyrrhizin possesses antiviral properties, potentially aiding the body in fighting off viral infections that cause colds and coughs. The antiviral effects have been observed in studies against various viruses, including certain coronaviruses.
Potential Benefits for Respiratory Health
Beyond its direct effects on coughs, liquorice may offer broader benefits for the respiratory system:
- Relieves Congestion: By acting as an expectorant, it helps reduce congestion and supports clear breathing.
- Soothes Asthma Symptoms: Some research suggests that glycyrrhizin may help relieve asthma due to its anti-inflammatory properties, though more human studies are needed.
- Supports the Immune System: The herb’s antiviral and antimicrobial properties help support the body's overall immune response to fight respiratory illnesses more effectively.
Comparative Analysis: Liquorice vs. Conventional Remedies
| Feature | Liquorice Root | Honey | Benzonatate (Tessalon Perles) | Guaifenesin (Mucinex) |
|---|---|---|---|---|
| Mechanism | Soothes irritated membranes (demulcent), loosens phlegm (expectorant), and provides anti-inflammatory/antiviral effects. | Coats the throat to soothe irritation and calm the cough reflex. | Anesthetizes receptors in the throat and lungs to suppress the cough reflex. | Thins and loosens mucus in the chest to make coughs more productive. |
| Active Ingredient | Glycyrrhizin, flavonoids, and saponins. | Sugars and other trace compounds. | Benzonatate. | Guaifenesin. |
| Best For | Both dry and wet coughs, sore throats, and fighting viral infections. | Soothing dry or scratchy throats. | Suppressing dry, non-productive coughs. | Loosening chest congestion and clearing wet coughs. |
| Potential Risks | High intake of glycyrrhizin can cause high blood pressure, low potassium, and fluid retention. | Generally safe, but can have high sugar content. | Requires a prescription; potential side effects include drowsiness, headaches, and numbness. | Generally well-tolerated; potential side effects include nausea and dizziness. |
Safety Concerns and Side Effects
Despite its benefits, liquorice containing glycyrrhizin should be used with caution. The compound can mimic the hormone aldosterone, leading to several health issues with high or prolonged consumption:
- Hypertension (High Blood Pressure): Fluid retention and increased blood pressure are significant risks.
- Hypokalemia (Low Potassium): Liquorice can cause the body to lose potassium, potentially leading to muscle weakness or heart rhythm issues.
- Drug Interactions: It can interfere with many medications, including diuretics, blood thinners (like warfarin), and blood pressure medication.
- Specific Contraindications: Individuals with heart conditions, kidney disease, liver disease, or high blood pressure should avoid liquorice containing glycyrrhizin.
An Alternative: Deglycyrrhizinated Liquorice (DGL)
For those seeking the soothing benefits of liquorice without the risks associated with glycyrrhizin, deglycyrrhizinated liquorice (DGL) is a safer alternative. DGL has been processed to remove the problematic compound, making it suitable for longer-term use, especially for digestive issues like ulcers and acid reflux. While DGL retains the demulcent properties that can soothe a sore throat, its expectorant, anti-inflammatory, and antiviral effects may be diminished compared to whole liquorice root.
How to Safely Use Liquorice for Coughs
For short-term symptomatic relief, consider these methods:
- Liquorice Tea: Brew a tea by steeping dried liquorice root in boiling water for 10–15 minutes. Combining it with other soothing herbs like ginger or mint can enhance the effects. A warm cup of tea is an excellent way to soothe an irritated throat.
- Gargle: A licorice root gargle can provide direct relief for a sore throat. Gargle with liquorice-infused water several times a day. Some clinical trials have shown effectiveness for postoperative sore throat, though it is less studied for common illnesses.
- Lozenges or Syrups: Over-the-counter licorice lozenges or syrups can be effective for soothing the throat. Check the glycyrrhizin content and opt for DGL products if you have health concerns.
- Chewing the Root: For centuries, chewing on a piece of liquorice root has been a simple, effective remedy for sore throats and hoarseness.
- Consult a Professional: Always talk to a healthcare provider before starting any new herbal remedy, especially if you have pre-existing health conditions or are taking other medications. You can find more detailed safety information from authoritative sources, such as this article from the University of Rochester Medical Center.
Conclusion
Liquorice can be an effective natural remedy for relieving coughs due to its powerful demulcent, expectorant, and anti-inflammatory properties. It is a traditional and scientifically recognized option for soothing sore throats and loosening mucus. However, the presence of glycyrrhizin in standard liquorice preparations poses significant health risks, particularly elevated blood pressure and low potassium, which necessitate cautious, short-term use and careful monitoring. For those with underlying health issues or who require long-term treatment, the safer DGL alternative should be considered. By understanding the properties and risks, individuals can make informed decisions about whether liquorice is the right remedy for their specific cough, always prioritizing consultation with a medical professional to ensure safe use.
