Lu Gan Shi 炉干石 — Chinese Herbal Medicine

Lu Gan Shi (炉干石) At a Glance

• Herb: Lu Gan Shi
• Chinese name: 炉干石 (Lu Gan Shi)
• Latin name: Calamina
• Nature: Neutral
• Taste: Sweet
• Meridian: Liver
• Category: Topical medication

Lu Gan Shi, the mineral Calamine (zinc carbonate/silicate), has been documented in Chinese medicine since the Song dynasty and features prominently in Li Shizhen’s *Ben Cao Gang Mu* as a topical workhorse for eye and skin disorders. Its neutral temperament and sweet, mildly astringent character allow it to dry dampness and clear heat without depleting yin, making it reliable for chronic weeping conditions where drying herbs might be too harsh. Clinically it anchors formulas for ocular inflammation, suppurating ulcers, and damp-heat eczema, almost always applied externally as a calcined, finely ground powder.

Actions & Therapeutic Effects

• Clears heat and resolves toxicity
• Dries dampness and stops discharge
• Brightens the eyes and reduces ocular redness
• Promotes tissue regeneration and wound healing
• Astringes to stop bleeding from superficial wounds

Clinical Applications in TCM

• Ocular redness, swelling, and purulent discharge: calcined powder dissolved in sterile water as an eye wash, often combined with Huang Lian (黄连) and Bing Pian (冰片)
• Chronic suppurating skin ulcers and non-healing sores: applied as a powder with Qing Fen (轻粉) and Ru Xiang (乳香) to dry exudate and promote granulation
• Weeping eczema (shi zhen, 湿疹): topical paste or wash with She Chuang Zi (蛇床子) and Ku Shen (苦参) to resolve damp-heat and relieve itching
• Corneal opacity and pterygium: traditionally calcined, levigated to an impalpable powder, and insufflated onto the eye surface
• Traumatic bleeding with damp ulceration: dusted alone or combined with Long Gu (龙骨) to astringe and form a dry healing crust

Precautions & Safety

• External use only; must be calcined (煅) and levigated to an extremely fine powder before ophthalmic or wound application to prevent abrasion.
• Avoid prolonged application over large open wounds due to systemic zinc absorption risk; contraindicated in patients with known zinc sensitivity or hypersensitivity to silicate minerals.

Classical TCM Formulas

• Lu Gan Shi Xi Yan (炉甘石洗眼): calcined Lu Gan Shi suspension for acute conjunctivitis.
• Lu Gan Shi San (炉甘石散): Lu Gan Shi + Huang Lian + Bing Pian — topical for eczema.
• Modern calamine lotion is the pharmaceutical descendant of Lu Gan Shi suspension.

Herb Combinations

• Lu Gan Shi (炉甘石) + Huang Lian (黄连) + Bing Pian (冰片) (topical): the classic ophthalmic and dermatological trio — astringes, clears Heat, penetrates.
• Lu Gan Shi (炉甘石) + Peng Sha (硼砂) + Bing Pian (冰片): compound powder for conjunctivitis.
• Lu Gan Shi (炉甘石) topical lotion: calamine-like suspension for eczema, urticaria, and prickly heat.

Pharmacology & Research

Zinc carbonate/oxide: delivers astringent and broad-spectrum antimicrobial action, directly accelerating wound closure and suppressing bacterial colonisation.
Silicates: form a physical barrier over ulcerated tissue, reducing trans-wound moisture loss and mechanical irritation.
Anti-inflammatory pathway: zinc ions inhibit phospholipase A₂ and prostaglandin E₂ synthesis, attenuating local erythema and oedema.

Classical Descriptions

• “爐甘石，甘，溫，無毒。止血，消腫毒，生肌，明目去翳，退赤，收濕除爛。” — *Ben Cao Gang Mu* (本草纲目), Li Shizhen (李時珍), 1578