Common Name: Gan Cao

General Information

Glycyrrhiza uralensis is a herbaceous perennial plant growing from a robust, rhizomatous rootstock. It produces a cluster of erect, branched or unbranched stems usually 30 - 70cm tall, occasionally reaching 120cm[].
Licorice root is one of the most commonly used herbal medicines and sweeteners/flavourings in the temperate zone, the roots being obtained from this species and also from Glycyrrhiza inflata and Glycyrrhiza uralensis. This species is harvested from the wild for local and commercial use, and also cultivated in gardens and for commercial use[].

Known Hazards

Whilst licorice is basically a very safe and effective medicine, when used over a long period or in large quantities it can raise the blood pressure. A gross overdose of the root can cause oedema, high blood pressure and congestive heart failure[, ].

Botanical References

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Range

Eurasia - Russian Federation (Orenburg to eastern Siberia), Kazakhstan, Kyrgyzstan, Tajikistan, Afghanistan, Pakistan, Mongolia, China

Habitat

Meadows, riparian woodlands and solonetzic slopes in Siberia[]. Sandy lands, dry riverbanks, grasslands on hills; at elevations from 400 - 2,700 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	0.60 m
Pollinators	Insects
Cultivation Status	Cultivated, Wild

Cultivation Details

Glycyrrhiza uralensis is a moderately cold-hardy plant, able to tolerate temperatures down to at least -15°c when fully dormant. The young growth in spring, however, is much more tender and can be damaged by light frosts[].
Requires a deep well cultivated fertile moisture-retentive soil for good root production[]. Prefers a sandy soil with abundant moisture[]. Slightly alkaline conditions produce the best plants[].
This species is widely cultivated in China as a medicinal plant. Unless seed is required, the plant is usually prevented from flowering so that it puts more energy into producing good quality roots[].
A very deep-rooted plant, it can be difficult to eradicate once it is established[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

The fibrous root is used as a sweetener for foods[]. It is boiled in water to extract the sugars etc and used as a liquorice substitute in sweets, medicines, drinks etc[, , ]. The root contains glycyrrhizin, which is 50 times sweeter than sugar[].

Medicinal

Gan Cao is commonly used in Chinese herbalism, where it is considered to be one of the 50 fundamental herbs[]. It is considered to be second in importance only to Ginseng (Panax spp)[]. Used in excess, however, it can cause cardiac dysfunction and severe hypertension[].

The root of this plant is one of the three main commercial sources of licorice (the other two are Glycyrrhiza glabra and Glycyrrhiza inflata). Studies have shown that the range and content of medicinally active compounds in Glycyrrhiza glabra and Glycyrrhiza inflata are very similar and that they can be used interchangeably. Glycyrrhiza uralensis, however, exhibits markedly different contents of the various active compounds and has subtly different applications medicinally. For example, the root of this species has a stronger oestrogenic activity than the other licorices, is a more powerful antitussive and also exerts a stronger inhibitory effect upon aldose reductase activity[].

The root is a sweet tonic herb that stimulates the corticosteroidal hormones, neutralizes toxins and balances blood sugar levels[]. It is also antibacterial, anti-inflammatory, antiphlogistic, antispasmodic, antitussive, cholagogue, demulcent, emollient, expectorant and laxative[, , , ].
It is used internally in the treatment of Addison's disease, asthma, coughs and peptic ulcers[].
Externally, it is used to treat acne, boils and sore throats[].
Gan Cao is included in almost all Chinese herbal formulae, where it is said to harmonize and direct the effects of the various ingredients[]. It precipitates many compounds and is therefore considered to be unsuitable for use with some herbs such as Daphne genkwa, Euphorbia pekinensis and Corydalis solida[]. It increases the toxicity of some compounds such as ephedrine, salicylates, adrenaline and cortisone[].
It should not be prescribed for pregnant women or for people with high blood pressure, kidney disease or anyone taking digoxin-based medications[]. Excessive doses cause water retention and high blood pressure[]. It can cause impotence in some people[].
The roots are harvested in early autumn, preferably from plants 3- 4 years old, and are dried for later use[].

The flowers are alterative and expectorant[].

Other Uses

Liquorice root, after the medicinal and flavouring compounds have been removed, is used in fire extinguishing agents, to insulate fibreboards and as a compost for growing mushrooms[].

An extract of the plant is used as an ingredient in commercial cosmetic preparations as an emollient and skin conditioner[].
An extract of the roots is used as an ingredient in commercial cosmetic preparations as a skin conditioner[].

Propagation

Pre-soak the seed for 24 hours in warm water and then sow spring or autumn in a greenhouse[]. Prick out the seedlings into individual pots when they are large enough to handle, and grow them on for their first winter in a greenhouse. Plant out in late spring or early summer when in active growth. Plants are rather slow to grow from seed[].
Division of the root in spring or autumn. Each division must have at least one growth bud. Autumn divisions can either be replanted immediately or stored in clamps until the spring and then be planted out[]. It is best to pt up the smaller divisions and grow them on in a cold frame until they are established before planting them out in the spring or summer.