Licorice Root (Gan Cao, Radix Glycyrrhizae)
Licorice root, also known as Gan Cao and Radix Glycyrrhizae, is one of well-known herbs primarily used as a harmonizer in Chinese herbal formulas. By contract, western clinical medicine uses it more as a moderator thanks to its anti-inflammatory, antispasmodic and antacid effects. In fact, this herb has long been used as medicine in ancient China since 2,000 years ago, which was recorded in the oldest herbology classic of “Shen Nong’s Herbal Classic” and listed as one of the superior drugs there. In addition, it was highly regarded as “the Teacher of Emperors” in the kingdom of herbs by Tao Hongjing, a famous physician in the Southern Dynasties (420-589). However, the most pertinent review about licorice comes from Li Shizhen, the writer of “Compendium of Materia Medica”, in which he said:” Licorice herb, as the monarch drug in prescriptions, inhibits the toxicities from 72 minerals and 1,200 grass and trees. As a result, it is revered as the Emperor’s Teacher for the credit of reconciling the rest herbs.” So, is licorice root safe? What is licorice root good for? These are good questions, but apparently it needs to answer the following one in the first place.
What is licorice root?
Medicinally it means the roots and rhizomes of Glycyrrhiza uralensis Fisch., G.inflata Bat., and G.glabra L. In China it is mainly produced in Inner Mongolia, Xinjiang, Gansu and other places. It is usually harvested during spring and autumn. Typically the one in autumn is preferred. After harvesting, remove its fibrous roots, dry it in the sun, and slice it thickly. And it is used raw or honey fried.
It is a perennial herb, 30 to 100cm high. Root is stout, cylindrical, sweet, and with red-brown or dark brown skin. Stems are erect, and with xylon base, which is covered with white short hairs and bristle-like glands. Leaves are odd pinnate, alternate, and with about 6cm petiole. Leaflets are 7 to 17, ovate-elliptic, 2 to 2.5cm long, 1 to 3cm wide, and with obtuse tip, rounded base, and surfaces covered with glands and short hairs. Raceme, densely flowered, grows from leaf axil in summer. Bell-shaped calyx is covered with short hairs and bristle-like glands. Legume, in the shape of bar and oblong, grows densely, and sometimes it looks like from falciform to ring, 6 to 9mm, , and densely covered with brown bristle-like glands. Seeds, 2 to 8, are disciform or slightly kidney-shaped.
Main chemical constituents of licorice root and rhizome are glycyrrhizin, which is the sylvite and calcium salt of glycyrrhizic acid. It also contains liquiritin, liquiritigenin, isoliquiritin, isoliquritigenin, neo-liquiritin, neoiso-liquiritin, and so on.
Licorice root benefits
This is not only one of the most common Chinese herbs, but also an indispensable one in many herbal formulas. This is simply because it is able to harmonize the efficacies of a variety of other herbs. However, the health benefits of licorice are far from that. Today, its ready-made products, including licorice root tea, chew sticks, extract, powder, supplement, are so popular. Western Pharmacology found that licorice has the anti-inflammatory and antiallergic functions.
Modern pharmacological actions of licorice herb
1. It fights arrhythmia;
2. It prevents ulcers, inhibits gastric acid secretion, relieves gastrointestinal smooth muscle spasm, eases pain, and works in coordination with Paeoniflorin, which is the active ingredient of peony;
3. It promotes the secretion of pancreatic juice;
4. It relieves cough significantly, makes expectoration easy, and prevents asthma to a certain extent;
5. It has antibacterial, antiviral, anti-inflammatory, anti-allergic effects;
6. It protects the inflamed mucous membranes of the throat and trachea;
7. It has a certain toxic glucuronide-like detoxification;
8. It has an effect similar to the adrenocortical hormone;
9. It counteracts diuresis, lowers lipid level, protects liver, and so on.
Popular herbal remedies on licorice roots
It is viewed as sweet in flavor and neutral in properties by practitioners of TCM (Traditional Chinese medicine). And it covers meridians of heart, lung, spleen, and stomach. Prime functions are invigorating spleen-stomach and replenishing qi, relieving urgency and stopping pain, moistening lung to arrest cough, purging fire for removing toxin, and coordinating the drug actions of a prescription. Key dried licorice root uses include lassitude and reduced appetite, emaciation with sallow complexion, palpitations and short of breath, abdominal pain and loose stools, pain and hypertonicity of the limbs, hysteria, cough and asthma, sore throat, skin ulcer, congenital disease, drug and food poisoning, and more. Recommended licorice root dosage is from 2 to 6 grams in decoction when used for moderating the property of herbs, about 10 gram when used as main herb of formula, and 30 to 60 grams in the case of poisoning.
Potential licorice root side effects and contraindications
Large doses or long-term taking licorice root may lead to a variety of adverse reactions in about 20% patients, including edema, weakness, cramps numbness, dizziness, headache, high blood pressure, hypokalemia and other symptoms. And it may make the elderly and people with cardiovascular disease and kidney disease prone to high blood pressure and congestive heart failure. In addition, long-term use of glycyrrhizin can cause lactation in non-lactating women.
From the perspective of TCM, Gan Cao is incompatible with Jing Da Ji (Euphorbia pekinensis), Yuan Hua (Genkwa Flower), and Gan Sui (Kan Sui Root). This herb comes with the disadvantages of encouraging dampness and congesting qi. So it shouldn’t be used in cases of fullness and edema due to excessive dampness. What’s more, long-term use of licorice in large doses can cause sodium retention and thus swelling.