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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Non-Standardized Food Allergenic Extract [EPC]
Licorice is a non-standardized food allergenic extract used primarily in diagnostic allergy testing and immunotherapy, belonging to the class of plant-derived allergenic extracts.
Name
Licorice
Raw Name
LICORICE
Category
Non-Standardized Food Allergenic Extract [EPC]
Drug Count
12
Variant Count
13
Last Verified
February 17, 2026
About Licorice
Licorice is a non-standardized food allergenic extract used primarily in diagnostic allergy testing and immunotherapy, belonging to the class of plant-derived allergenic extracts.
Detailed information about Licorice
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Licorice.
Licorice belongs to a class of drugs called allergenic extracts. These are unique because they are not traditional synthetic chemicals but are complex mixtures of proteins and polysaccharides derived from the source material. The FDA (Food and Drug Administration) regulates these extracts under the Center for Biologics Evaluation and Research (CBER). Historically, licorice root has been used for millennia in traditional Chinese medicine and Greek medicine for various ailments, but its modern clinical application as an allergenic extract focuses on the identification of IgE-mediated (Immunoglobulin E) sensitivities.
It is crucial to distinguish between the clinical allergenic extract and the dietary supplement or food product. The allergenic extract is used under strictly controlled medical environments to provoke a localized immune response for diagnostic purposes. Talk to your healthcare provider to understand if you are being tested with this specific extract or if you are using licorice in its herbal form for other therapeutic reasons.
The mechanism of action for Licorice as an allergenic extract is rooted in the human immune system's Type I hypersensitivity response. When a patient who is sensitized to licorice proteins is exposed to the extract via skin prick testing or intradermal injection, the specific IgE antibodies bound to the surface of mast cells and basophils (types of white blood cells) recognize the licorice allergens. This recognition triggers a process called degranulation, where the cells release inflammatory mediators, most notably histamine, leukotrienes, and prostaglandins.
At the molecular level, these mediators cause localized vasodilation (widening of blood vessels) and increased capillary permeability, leading to the characteristic 'wheal and flare' reaction (a raised, itchy bump surrounded by redness). This reaction allows clinicians to visually confirm the presence of an allergy.
In its non-extract, pharmacological form (such as the whole root or its primary active constituent, glycyrrhizin), licorice works by inhibiting the enzyme 11-beta-hydroxysteroid dehydrogenase (11-β-HSD2). This enzyme is responsible for converting active cortisol into inactive cortisone. By inhibiting this enzyme, licorice allows cortisol to act on mineralocorticoid receptors in the kidney, mimicking the effect of aldosterone. This leads to sodium retention and potassium excretion, which explains many of its systemic side effects and therapeutic uses in conditions like Addison's disease (though this is rare in modern practice).
Because Licorice allergenic extracts are typically administered via the skin (epicutaneous or intradermal) for diagnostic purposes, their systemic pharmacokinetic profile differs significantly from oral licorice consumption.
The primary FDA-recognized use for Licorice (Non-Standardized Food Allergenic Extract) is in the diagnosis of IgE-mediated allergies. This is performed through:
Off-label or traditional uses of licorice (not necessarily the allergenic extract form) include:
Licorice is available in several distinct forms depending on the intended use:
> Important: Only your healthcare provider can determine if Licorice is right for your specific condition. Diagnostic extracts must only be administered by trained medical professionals in facilities equipped to handle anaphylaxis.
Dosage for Licorice varies significantly based on the form and the clinical objective.
For skin prick testing, a single drop of the extract (typically at a concentration of 1:10 or 1:20 w/v) is applied to the volar surface of the forearm or the back. For intradermal testing, the dose is much smaller, usually 0.02 to 0.05 mL of a highly diluted extract (e.g., 1:100 or 1:1000 w/v).
Licorice allergenic extracts are used in children for allergy testing. The procedure is identical to adult testing, though the number of tests performed at one time may be limited by the child's size and tolerance.
Licorice is generally not recommended for therapeutic use in children without strict medical supervision. There is a lack of robust safety data regarding the long-term effects of glycyrrhizin on the developing endocrine system in pediatric patients. Use in infants is strictly contraindicated due to the risk of electrolyte imbalances.
Patients with kidney disease should avoid licorice products containing glycyrrhizin. The sodium-retaining and potassium-wasting effects of licorice can exacerbate renal failure, increase blood pressure, and lead to fluid overload. If diagnostic testing is required, the risk is lower but should still be discussed with a nephrologist.
Licorice is metabolized in the liver. Patients with cirrhosis or hepatitis may experience prolonged half-lives of licorice components, increasing the risk of toxicity. Dose reductions or complete avoidance are typically recommended for oral forms.
Older adults are at a higher risk for licorice-induced hypertension and hypokalemia (low potassium). Healthcare providers typically recommend lower doses and frequent monitoring of blood pressure and electrolytes in this population.
This form is never self-administered. It is administered by an allergist. You should avoid taking antihistamines (e.g., diphenhydramine, loratadine) for 3 to 7 days before the test, as these medications can suppress the skin reaction and lead to false-negative results.
If you are using licorice for a therapeutic purpose and miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and resume your regular schedule. Do not double the dose to catch up, as this increases the risk of potassium depletion.
An overdose of licorice (specifically glycyrrhizin) leads to a condition called 'pseudoaldosteronism.' Signs of overdose include:
In case of suspected overdose, seek emergency medical attention immediately or contact a poison control center. Treatment typically involves stopping all licorice intake, administering potassium supplements, and using potassium-sparing diuretics like spironolactone under medical supervision.
> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance.
When used as a diagnostic allergenic extract, the most common side effect is a localized skin reaction at the site of testing. This includes:
When consumed orally in non-DGL forms, common effects include:
> Warning: Stop taking Licorice and call your doctor immediately if you experience any of these.
Prolonged use of licorice containing glycyrrhizin can lead to chronic health issues:
No FDA black box warnings currently exist for Licorice (Non-Standardized Food Allergenic Extract). However, clinical guidelines emphasize that allergenic extracts should only be administered in settings where emergency equipment for treating anaphylaxis is immediately available.
Report any unusual symptoms to your healthcare provider. If you notice persistent swelling or heart palpitations, these must be evaluated by a medical professional immediately.
Licorice is not a simple herb; it is a potent pharmacological agent. Patients must be aware that 'natural' does not mean 'safe.' The most critical safety point regarding licorice is its ability to alter the body's electrolyte balance, specifically by lowering potassium and raising sodium. This can have cascading effects on the heart, kidneys, and nervous system.
No FDA black box warnings for Licorice. However, practitioners are warned that the potency of non-standardized extracts can vary between lots, necessitating cautious administration when switching to a new vial of extract.
If a healthcare provider prescribes licorice for therapeutic use, or if a patient is undergoing long-term immunotherapy with licorice extract, the following may be monitored:
Licorice generally does not affect the ability to drive or operate machinery. However, if a patient experiences a severe allergic reaction during testing or develops a hypertensive headache, they should refrain from these activities until symptoms resolve completely.
There is no direct interaction between licorice and alcohol. However, alcohol can exacerbate the blood-pressure-raising effects of licorice and may further irritate the gastrointestinal lining if the licorice is being used for ulcers.
For most people, licorice can be stopped abruptly. However, if it has been used in high doses for a long period, the body's salt-water balance may take several days or weeks to normalize. Tapering is not usually required, but close monitoring of blood pressure and potassium should continue for a short period after discontinuation.
> Important: Discuss all your medical conditions with your healthcare provider before starting Licorice.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking.
Licorice must NEVER be used in the following circumstances:
Conditions requiring careful risk-benefit analysis by a physician:
Patients who are allergic to other members of the Fabaceae (legume) family, such as peas, beans, soy, or peanuts, may occasionally show cross-reactivity to licorice allergenic extracts. This should be considered during diagnostic testing.
> Important: Your healthcare provider will evaluate your complete medical history before prescribing Licorice.
Licorice is generally considered unsafe during pregnancy. According to several epidemiological studies, high consumption of glycyrrhizin (more than 500 mg per week) is associated with a significantly higher risk of preterm delivery. Furthermore, licorice may affect the development of the fetal brain; some research suggests that children exposed to high levels of licorice in utero may have lower cognitive scores and increased behavioral problems later in life. It is classified as Category C or avoided entirely in most clinical guidelines.
There is limited data on the passage of licorice components into breast milk. However, because glycyrrhetinic acid is highly protein-bound, small amounts may reach the infant. Due to the potential for electrolyte disturbances in a nursing infant, breastfeeding women are advised to avoid therapeutic doses of licorice. Small amounts found in food are generally considered acceptable.
Licorice allergenic extracts are approved for use in children for the purpose of allergy diagnosis. However, the therapeutic use of licorice supplements in children is not recommended. Children are more sensitive to the electrolyte-altering effects of glycyrrhizin, and there is a risk of growth interference if used long-term due to its effects on the adrenal-pituitary axis.
Elderly patients are the most vulnerable population regarding licorice-induced side effects. They have a higher baseline risk of hypertension, cardiovascular disease, and renal decline. Furthermore, polypharmacy (taking multiple medications) in the elderly increases the likelihood of a dangerous drug interaction, especially with diuretics or heart medications. Healthcare providers should use the lowest possible dose and monitor electrolytes weekly in older adults.
In patients with impaired kidney function, the half-life of licorice metabolites is prolonged. The sodium-retaining effect of licorice can lead to rapid-onset edema and worsening of kidney function. Licorice is generally avoided in patients with a GFR (Glomerular Filtration Rate) below 30 mL/min.
Since the liver is responsible for the metabolism and biliary excretion of glycyrrhetinic acid, patients with hepatic impairment (Child-Pugh Class B or C) are at a much higher risk of toxicity. Licorice should be used with extreme caution or avoided in patients with chronic liver disease or cirrhosis.
> Important: Special populations require individualized medical assessment.
Licorice contains several active compounds, the most significant being glycyrrhizin (glycyrrhizic acid).
The onset of the mineralocorticoid effect usually occurs within 24 to 48 hours of oral ingestion, but the full effect on blood pressure may take 1 to 2 weeks to manifest. The duration of effect can be prolonged; even after stopping licorice, it can take several weeks for the 11-β-HSD2 enzyme to regain full activity and for potassium levels to normalize.
| Parameter | Value |
|---|---|
| Bioavailability | ~30-50% (as glycyrrhetinic acid) |
| Protein Binding | >95% (to Albumin) |
| Half-life | 3.5 to 30 hours |
| Tmax | 4 to 12 hours |
| Metabolism | Hepatic (Glucuronidation) |
| Excretion | Biliary/Fecal (Primary), Renal (Minor) |
Licorice is classified as a Non-Standardized Plant Allergenic Extract. In the broader pharmacological sense, it is often categorized as a secretolytic (expectorant) and a demulcent (soothing agent) in traditional pharmacopeias.
Common questions about Licorice
Clinically, Licorice is primarily used as a non-standardized allergenic extract to diagnose IgE-mediated allergies through skin testing. In broader medicine, deglycyrrhizinated licorice (DGL) is used to treat digestive issues like heartburn, acid reflux, and stomach ulcers by promoting protective mucus production. Some people also use it as an expectorant to help clear mucus from the respiratory tract during a cough or cold. However, it should only be used for these purposes under the guidance of a healthcare provider. It is important to distinguish between the flavoring in candy and the medicinal root extract.
The most common side effects of licorice, especially when it contains glycyrrhizin, include fluid retention, swelling in the hands and feet (edema), and an increase in blood pressure. Some individuals may also experience headaches or a general feeling of fatigue. If used as an allergy test, the most common effects are local itching, redness, and a raised bump at the site of the test. These local reactions are expected and usually disappear within a few hours. Always report persistent or worsening side effects to your doctor.
While there is no known direct chemical interaction between licorice and alcohol, it is generally advised to be cautious. Alcohol can independently raise blood pressure and cause dehydration, which may complicate the electrolyte imbalances that licorice can cause. If you are using licorice to treat a stomach ulcer, alcohol should be avoided as it can irritate the stomach lining and slow the healing process. Consult your healthcare provider about your specific situation regarding alcohol consumption. Monitoring your blood pressure is particularly important if you consume both.
Licorice is generally considered unsafe for use during pregnancy, particularly in large amounts. Research has linked high intake of glycyrrhizin to an increased risk of preterm labor and delivery. Additionally, some studies suggest that heavy licorice consumption during pregnancy may lead to long-term developmental or behavioral issues in the child. Most healthcare providers recommend that pregnant women avoid licorice-containing supplements and limit their intake of licorice-flavored foods. Always discuss any herbal or dietary supplements with your obstetrician before use.
The time it takes for licorice to work depends on the form and the condition being treated. For allergy skin testing, the reaction is almost immediate, usually peaking within 15 to 20 minutes. For digestive issues using DGL, some patients report relief from heartburn or indigestion within 30 minutes of taking a chewable tablet. However, for systemic effects like anti-inflammatory benefits or respiratory support, it may take several days of consistent use. If you are using it for a specific medical condition and do not see improvement within a week, contact your doctor.
For most individuals taking standard doses, licorice can be stopped suddenly without experiencing withdrawal symptoms. However, if you have been consuming very high doses of licorice containing glycyrrhizin for a long period, your body's salt and water balance may have adjusted to the herb. Stopping abruptly in this case might cause a temporary shift in electrolytes as your adrenal system recalibrates. It is always best to consult with your healthcare provider before stopping any long-term supplement. They can help monitor your blood pressure and potassium levels during the transition.
If you miss a dose of a licorice supplement, take it as soon as you remember. If it is nearly time for your next scheduled dose, skip the missed dose and continue with your regular routine. Do not take two doses at once to make up for the one you missed, as this can increase the risk of side effects like high blood pressure or low potassium. Consistency is key for therapeutic effects, but safety is more important. If you find yourself frequently missing doses, consider using a pill organizer or setting a reminder.
Licorice can cause a rapid increase in weight, but this is typically due to water retention rather than an increase in body fat. The glycyrrhizin in licorice causes the kidneys to hold onto sodium and water, which leads to swelling and a higher number on the scale. If you notice a sudden weight gain of several pounds over just a few days while taking licorice, this is a sign of fluid overload and should be reported to your doctor immediately. This fluid retention can put extra strain on the heart and kidneys. Weight usually returns to baseline once the licorice is discontinued.
Licorice has many significant drug interactions and should be used with caution if you are taking other medications. It is particularly dangerous when combined with diuretics, digoxin, or blood pressure medications, as it can lead to life-threatening potassium depletion. It may also interfere with the effectiveness of blood thinners like warfarin and certain hormone therapies. Because it affects liver enzymes, it can change how your body processes many different drugs. Always provide your healthcare provider with a full list of all medications and supplements you are currently taking.
Licorice is a natural substance and is not 'patented' in the way synthetic drugs are, so it is widely available from many different manufacturers as a generic herbal supplement. In the context of allergenic extracts for medical testing, these are produced by various biological laboratories and are generally referred to by their common name rather than a brand name. When buying supplements, look for products that specify whether they are 'standardized licorice' (containing glycyrrhizin) or 'DGL' (deglycyrrhizinated), as these have very different safety profiles. Quality can vary between brands, so choose reputable sources.