Gan Cao (Licorice Root TCM)

What is Gan Cao (Licorice Root TCM)?

Gan Cao (Glycyrrhiza uralensis) is the single most commonly used herb in all of Traditional Chinese Medicine — appearing in roughly half of all classical TCM formulas. It is considered a 'guide herb,' meaning it helps other herbs in a formula work better together and reduces their harshness on the body. The root is naturally very sweet, which is why its Latin name means 'sweet root,' and it has been used in Chinese medicine for over 3,000 years.

How does Gan Cao (Licorice Root TCM) work?

The main active compound, glycyrrhizin, is a powerful anti-inflammatory that slows down the breakdown of cortisol in your body, giving your adrenal system a bit of extra support during times of stress. Other compounds like liquiritin and glabridin act as antioxidants and help soothe irritated tissue in the gut and respiratory tract. Together, these compounds reduce inflammation, support the immune system, and protect mucosal surfaces like your stomach lining and throat.

What forms does Gan Cao (Licorice Root TCM) come in?

For digestive issues, DGL chewable tablets are the preferred form — they've had glycyrrhizin removed so they're safe for longer use without blood pressure concerns. For adrenal support, stress, or immune purposes, whole-root extracts or standardized capsules retaining glycyrrhizin are used. Zhi Gan Cao (honey-fried licorice) is a specific TCM preparation believed to strengthen the heart and qi. Traditional decoctions are common in Chinese herbal medicine when Gan Cao is used as part of a formula.

Where it comes from:

Gan Cao has the longest and most widespread herbal record in Chinese medicine, first documented in the Shennong Bencao Jing (Divine Farmer's Classic of Materia Medica) around 200 AD, where it was classified as a 'superior herb.' It has also been used in Persian medicine (Unani), Ayurveda, and ancient Greek and Roman medicine, making it one of the most globally recognized medicinal plants in human history.

What does Gan Cao (Licorice Root TCM) help with?

• Digestive discomfort and stomach ulcers: Licorice root — especially the DGL form — helps coat and protect the stomach lining, reducing irritation from acid and supporting the healing of ulcers. It works by boosting the mucus layer in the stomach, which acts like a protective barrier against damage.
• Sore throat and cough: Gan Cao has long been used to ease sore, scratchy throats and calm dry or irritated coughs. Its soothing compounds help reduce swelling and irritation in the throat and airways, making it a go-to ingredient in TCM respiratory formulas.
• Adrenal fatigue and chronic stress: Glycyrrhizin slows the breakdown of cortisol in the body, which means your stress hormone stays active a bit longer — helpful when your adrenal glands feel depleted or sluggish after prolonged stress. This makes Gan Cao a common herb in TCM formulas for people who feel chronically exhausted or run down.
• Leaky gut and gut inflammation: The anti-inflammatory compounds in licorice root help calm an irritated gut lining and may support the repair of a compromised gut barrier. It's often included in protocols for gut permeability because it reduces inflammation while also soothing the mucosal surface.
• Heartburn and acid reflux: DGL licorice is one of the more well-studied natural options for relieving heartburn and reflux discomfort. It works not by blocking acid but by strengthening the stomach's own defenses, including the mucus layer that protects against acid damage.
• Skin inflammation and eczema: Topical licorice extract — particularly its compound glabridin — has anti-inflammatory effects that can help calm redness, itching, and irritation in conditions like eczema and dermatitis. It's gentle enough for sensitive skin and is used in many natural skincare formulations.
• Viral infections and immune support: Glycyrrhizin has shown antiviral activity against several viruses in research settings, and Gan Cao is commonly used in TCM during colds and flu to support the immune response and shorten the duration of illness. It's rarely used alone — it's typically part of a formula.
• Menopausal symptoms: Licorice root contains phytoestrogenic compounds that can gently mimic estrogen in the body, which may help ease hot flashes and other symptoms of menopause. Several clinical studies have looked at this, particularly for women who prefer not to use hormone therapy.
• Liver health and protection: Intravenous glycyrrhizin preparations have been used in Japan for decades to treat chronic hepatitis and protect the liver, and oral forms show some of the same anti-inflammatory and liver-protective effects in research. It's an important herb in TCM liver formulas.
• Hormonal imbalance (PCOS): Some research suggests licorice root may help lower testosterone levels in women with PCOS by supporting hormonal balance. It's not a standalone treatment but is sometimes used as part of a broader naturopathic approach to PCOS management.

What can Gan Cao (Licorice Root TCM) help prevent?

• Recurrence of peptic ulcers (DGL form, with evidence from clinical use and trials)
• Liver damage from chronic hepatitis B and C (supported by decades of Japanese clinical use of glycyrrhizin preparations)
• Oral mucositis during chemotherapy (emerging evidence from clinical trials)

Which foods are rich in Gan Cao (Licorice Root TCM)?

1. Fermented foods (sauerkraut, kefir, kimchi): Support the gut microbiome and mucosal health — complementary to licorice root's gut-soothing effects
2. Turmeric: Powerful anti-inflammatory that works along the same pathways as licorice root's flavonoids
3. Bananas and leafy greens: Rich in potassium, which is important to maintain when using whole licorice root, since glycyrrhizin can lower potassium
4. Ginger: Soothes the digestive tract and reduces nausea, complementing licorice root's digestive benefits
5. Bone broth: Supports gut lining repair with collagen and amino acids, working alongside licorice root's mucosal protection

Practical Tips:

Licorice root is not found in meaningful amounts in everyday foods — it's used as a flavoring agent in small quantities in some candies and teas, but not at therapeutic levels. To support the same goals (gut soothing, anti-inflammation, adrenal support), focus on: fermented foods like sauerkraut and kefir to support gut health; turmeric and ginger for their anti-inflammatory effects; leafy greens, avocado, and bananas to support potassium levels (important when using whole licorice root); and adaptogenic teas like ashwagandha or holy basil for adrenal support. Avoid excessive salt, alcohol, and caffeine when taking whole-root licorice, as these can compound blood pressure effects.

What are the side effects of Gan Cao (Licorice Root TCM)?

• High blood pressure (pseudoaldosteronism: a well-documented risk with high-dose or long-term whole-root use)
• Low potassium (hypokalemia): can cause muscle weakness, cramping, or irregular heartbeat
• Fluid retention and swelling (especially in the ankles)
• Headaches with high doses
• Fatigue or hormonal disruption with very prolonged use
• Possible worsening of hormone-sensitive conditions (endometriosis, certain cancers) due to phytoestrogenic activity
• Not recommended during pregnancy at therapeutic doses: associated with preterm birth risk in high-intake observational studies

Good to know:

Gan Cao is considered very safe at normal doses for short-term use (under 4-6 weeks). The main concerns arise with whole-root licorice (containing glycyrrhizin) taken in high doses or for long periods. DGL form removes most of the risky compound and is much safer for ongoing use. Pregnant women should avoid therapeutic doses of whole licorice root.

How much Gan Cao (Licorice Root TCM) should you take?

• Recommended daily: Whole root extract (standardized to glycyrrhizin): 1–4g dried root equivalent daily, or 200–600mg glycyrrhizin. DGL tablets for digestive use: 380–1,140mg (chewed) before meals. TCM decoction: 2–10g dried root per day as part of a formula. Do not exceed 100mg glycyrrhizin per day for prolonged use.
• Best time of day: For digestive issues, take DGL 20–30 minutes before meals. For adrenal and stress support, morning dosing is preferred to align with the natural cortisol rhythm.
• With or without food: DGL should be chewed before meals on an empty stomach for best digestive effect. Capsule or extract forms are generally fine with food and may be better tolerated that way.
• Time to effect: Throat and digestive soothing: within 1–3 days. Gut lining repair and adrenal support: 4–8 weeks of consistent use.
• How long to take it: Limit whole-root licorice (with glycyrrhizin) to 4–6 weeks of continuous use. DGL form can be used longer with less concern. If using for more than 6 weeks, take a 4-week break or consult a practitioner. Monitor blood pressure if using whole root for more than 2 weeks.