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1 Herbal profile
2 Traditional uses
3 Historical Context and Curiosities
4 Use of liquorice in horses
5 Contraindications
6 Sources

Herbal profile

NameLiquorice, also known as liquorice wood, liquorice root, sweet stalk, sugar wood, licorice twig or sweet herb.
Latin nameGlycyrrhiza glabra (Leguminosae)
Traditional usesThe boiled decoction of liquorice root is used for coughs and stomach complaints, i.e. inflammatory diseases of the mucous membranes. The leaves are used externally for eczema and itching.
Scientifically proven effect(s)Contains the glycoside glycyrrhizin with 50 times the sweetening power of household sugar, over 40 different flavonoids, including liquiritin and liquiritigenin. Glycyrrhizin inhibits the breakdown of cortisol and aldosterone, which explains its strong anti-inflammatory effect (cortisol), but can cause high blood pressure and kidney damage (aldosterone) if administered over a longer period of time. It has a particularly strong anti-inflammatory effect, as well as antibacterial, fungicidal, diuretic, expectorant, expectorant and analgesic properties. It is mainly used for inflammatory gastrointestinal diseases (especially stomach ulcers) and respiratory problems (especially chronic coughs)
ContraindicationsCaution: Inhibits the body’s own cortisol and aldosterone breakdown, so never feed for more than 3 weeks at a time! Too frequent or too high a dose can lead to an increase in blood pressure and cause lasting damage to the kidneys. Do not feed to pregnant mares or horses with impaired kidney, liver or heart function. Do not feed to horses at risk of laminitis, as increased cortisol levels are suspected of being able to trigger laminitis!
When is it collected?Roots are dug up in autumn.
Which parts of the plant are usedMainly the root. For external use also the leaves.
How is it prepared?Liquorice root must be boiled for 10 minutes and then strained. Scald 2-3 teaspoons of liquorice root with ¼ – 1 litre of boiling water, simmer for 10-15 minutes over a low heat and strain, feed the brew.
TriviaHome of the plant: Mediterranean region, but subspecies can be found all over the world. In Germany, it is only cultivated in the region around Bamberg; most liquorice is imported from India. First documented use in Egypt 3000 years ago Napoleon Bonaparte is said to have always carried some liquorice with him. Described here in 1925 in ‘Hager’s Handbook of Pharmaceutical Practice’. Dried liquorice sticks are used as ‘natural toothbrushes’, as the wood defibres strongly when you chew on it and thus cleans your teeth. The expression ‘to grate liquorice’ is used for flattering compliments when a man is courting a woman. Accordingly, ‘sweet-talker’ is a mocking term for someone who tries to ingratiate himself. Up until the 17th century, the phrase ‘sweet-talking’ was used when someone tried to appease another with obsequious gestures.

Traditional uses

The liquorice plant has long been known for its healing properties and, with its approximately 400 different ingredients, was voted medicinal plant of the year 2012. The main active ingredient is glycyrrhizin, which has 50 times the sweetening power of ordinary household sugar.

The root is mainly used for dry coughs or inflammatory stomach complaints, such as gastritis or stomach ulcers. In the past, liquorice root was boiled together with fennel, ginger and aniseed in water or beer and given as a potion to treat coughs.

Historical Context and Curiosities

The name of the liquorice plant is due to its sweet taste and its woody branches. The Latin name Glycyrrhiza is made up of the Greek words ‘glycys’ (sweet) and ‘rhiza’ (root). The plant is mainly native to the Mediterranean region, but subspecies can be found worldwide. Like so many medicinal plants, liquorice has spread all over the world through sea trade.

In Central Europe, liquorice has been used as a medicinal plant since the Middle Ages. From the middle of the 18th century, sweets made from liquorice, sugar and flour were sold in British pharmacies to treat coughs. However, it was probably the ancient Egyptians who first utilised it. According to tradition, the plant was found in the tomb of King Tut 3000 years ago. They also knew of a liquorice drink called ‘Mai sus’. Traditional Chinese medicine has also long recognised liquorice – fresh or roasted – as a phytotherapeutic agent.

Even today, liquorice is still important in several areas. Liquorice is not only a remedy, but also a tasty snack. The liquorice root is a raw material for liquorice production, for which it is washed, peeled, dried, grated and then boiled in water. The liquorice juice is then thickened at low heat to form a solid mass and processed into various types of liquorice. Extracts from the plant are used as flavour enhancers in beer, herbal liqueurs, and soft drinks or to flavour tobacco. Extract residues can be used as compost in mushroom cultivation or in animal feed. The fibre waste is pressed and used as building board and in the fire extinguishing agent industry.

Use of liquorice in horses

Due to its strong anti-inflammatory effect on the mucous membranes, the use of liquorice is particularly suitable for soothing inflammation of the stomach and intestinal mucosa. In a study with 12 donkeys, which investigated the prophylactic effect of liquorice root extract on gastric ulcers in equidae after administration of painkillers, a placebo group, a group that only received the painkiller and a third group with painkiller and additional liquorice root extract were examined.

Around 20% of stomach ulcers are located in the pyloric region, the back of the stomach. These are mainly triggered by permanent stress, which can be intrinsic or extrinsic, and which results in reduced blood flow to the stomach lining, which is then no longer able to maintain the natural mucus barrier. The irritation caused by the stomach acids then leads to gastritis and, in the long term, to stomach ulcers, which cause pain and therefore even more stress.

In the study on the donkeys, the animals were examined gastroscopically and by blood diagnosis for EGGD lesions (Equine Glandular Gastric Disease), i.e. gastric ulcers in the posterior, glandular stomach area. The examinations were carried out on day 0 (reference) and after 7 test days. On the first day, with the exception of one animal, no other animals showed EGGD lesions. After one week, severe EGGD lesions were observed in all donkeys in the second group (painkillers), but only slight changes were observed in animals in the third group (painkillers and liquorice). There were no changes in the placebo group. Not only was the severity of the gastric ulcers reduced by the liquorice root extract, but the hypoglycaemia induced by the drug and possible liver damage were also reduced by the liquorice.

The use of liquorice is therefore recommended for horses with gastritis or proven stomach ulcers to soothe and help them heal. However, glycyrrhizin falls under the doping rules, so it should not be given to sport horses.

In addition to its potent effect on inflammation in the digestive tract, the plant has an expectorant, antibacterial and soothing effect, which can also help with respiratory problems. Especially in horses with chronic (dry) coughs, liquorice (extract) can often bring relief quite quickly. Of course, a cure is only possible here if the causes and triggers for the chronic cough are simultaneously eliminated or therapeutically addressed.

As the liquorice root cannot be sufficiently broken down by the horse, it should always be boiled, or alternatively the ready-made liquorice extract should be used. It should be noted that liquorice should never be used in therapeutic quantities for longer than three weeks at a time, as it inhibits the body’s own cortisol and aldosterone breakdown, which can lead to health complications ranging from laminitis to kidney failure.

The following treatment has proven itself in horse feeding:

  • Feed 1-2 teaspoons of liquorice extract daily for 2 weeks (alternatively the decoction of 2-3 teaspoons of boiled liquorice root)
  • 2 weeks break
  • Feed 1-2 teaspoons of liquorice extract daily for 2 weeks (alternatively the decoction of 2-3 teaspoons of boiled liquorice root)

A longer break should be taken after the treatment.

This treatment is mainly reflected in a six-week intestinal cleanse, during which bitter herbs (30-50 g per day) are also given continuously throughout the six weeks to stabilise the intestines. The combination of liquorice root and bitter herbs helps to soothe inflamed mucous membranes, stabilise the microbiome in the large intestine and thus contribute to improved overall health of the digestive tract.

For eczema and itchy skin, external rubbing with fresh, crushed liquorice leaves is also recommended, but as the plant is rarely cultivated locally, this is difficult to implement in practice.

Contraindications

The active ingredient in liquorice root (glycyrrhizin) inhibits the breakdown of the body’s own cortisol in the liver. This increases the cortisol level, which is responsible for the anti-inflammatory effect in the body.
But anyone who has ever had to deal with cortisone prescribed by a doctor knows that it is a double-edged sword: given in the short term, it is a fantastic anti-inflammatory. If given long term, it can cause all sorts of (entirely new) health problems, as it also inhibits the immune system, drives up blood sugar levels and causes progressive protein breakdown in the body.
Therefore, liquorice should only ever be given to all horses for a short period of time; as already described, we usually recommend giving it for 2 weeks, then taking a break.

In patients at risk of laminitis, cortisone is suspected of triggering an acute episode of laminitis. The study situation here is not entirely clear, but we prefer to be on the safe side and therefore recommend avoiding liquorice in cases of laminitis (which is a potentially fatal disease).
EMS initially only refers to a horse with excessive fat deposits, which is the main symptom. EMS can go hand in hand with insulin resistance, but not necessarily. There are also horses that are simply fat. A distinction must be made between horses with pseudo-EMS, i.e. overweight caused by lymphatic deposits. There are also mixed forms – horses that suffer from both fat and lymphatic deposits. Horses with pseudo-EMS can also have insulin resistance, but this is not always the case.
Horses with Cushing’s symptoms are also often insulin resistant. According to studies, around 60% of horses with Cushing’s symptoms also have insulin resistance. But there are also the other 40%. And there are normal-weight or even rather slim horses that can have insulin resistance. Horses with insulin resistance should generally not be given liquorice extract as it increases the blood sugar level.

However, in individual cases it also depends on the symptoms the horse shows, how pronounced the insulin resistance is and how the horse’s exercise management is handled. If the horse with its insulin resistance is exercising properly every day, then there is nothing to be said against a short course of liquorice extract if this is indicated, e.g. to calm the chronically inflamed airways so that the horse can breathe better and therefore training better.

The same applies to horses with clinically manifest PSSM. In the case of PSSM, a distinction must be made between horses with a genetic predisposition – where liquorice extract can certainly be given as a two-week treatment if, for example, it is indicated to stabilise the digestive tract or for chronic respiratory problems.

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In the case of clinically manifest PSSM, other issues are in the foreground for the time being; liquorice extract would not be used in this case nor would it be recommended.

As is so often the case with metabolic problems in horses – the reality is somewhat more involved then it lets on to begin with . Therefore, for horses with clinically manifest metabolic symptoms – whether it is the overweight EMS horse, the underweight horse with insulin resistance, or a horse with a history of laminitis, a Cushing’s diagnosis or a genetic predisposition to PSSM – it is always recommended to consult a competent therapist who can help you to put together a suitable nutrition and therapy plan for the individual horse and its health problems. Otherwise, a well-intentioned (but unfortunately wrong for this horse) therapy can do more harm than good.
The same applies to herbs: they interfere with the metabolism and where there is an effect, there is always a potential side effect.

Sources

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Further herbal advice can be found here: Sanoanimal herbal advice for horse feeding

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