This product is a mercury compound primarily containing mercurous chloride, made by sublimation through calcination using mercury, chalcanthite, and table salt as raw materials. It is produced in Hubei, Hunan, Hebei, Tianjin, Yunnan, and other regions. The process involves dissolving chalcanthite and table salt in water, then adding mercury to form a paste, which is mixed with red clay and shaped into lumps. These lumps are placed on a layer of dry sand in a flat-bottomed pan, covered with a porcelain basin, and sealed. They are then calcined with charcoal for about 10 hours, after which snowflake-like crystals, known as calomel, can be seen adhering to the inside of the porcelain basin.

bubble_chart Morphological Characteristics

This product appears as snowflake-like crystals or fine powder, white in color with a slight luster. Prolonged exposure to sunlight may cause it to turn grayish-yellow and dull, and it turns black upon contact with ammonia water. It is relatively light in weight and easily crumbles into powder when rubbed between fingers. It is odorless and has a mild taste. This product is highly toxic and must not be ingested. The best quality is characterized by large, flaky or snowflake-like pieces, white color, luster, and lightness.

bubble_chart Properties and Meridians

Acrid, cold. act on large intestine and small intestine channels. extremely toxic.

bubble_chart Efficacy

Dispelling phlegm, eliminating stagnation, promoting diuresis, and relieving constipation.

bubble_chart Indications

External use: killing worms, attacking toxins, and astringing sores. Used for sores and scabies, cervical neurodermatitis, sores and ulcers, eczema, grind into powder and apply to the affected area.

Internal use: dispelling phlegm and eliminating stagnation. Used for expelling water and promoting bowel movements, phlegm and saliva retention, food retention, edema and distension, and difficulty in urination and defecation.

bubble_chart Usage and Dosage

The usual dosage is 0.1 to 0.28 grams, often taken in pill form or encapsulated; for external use, apply an appropriate amount by grinding into a fine powder and sprinkling or mixing to apply on the affected area.

bubble_chart Cautions and Contraindications

bubble_chart Processing and Storage

This product should be stored in a light-proof, sealed container.

bubble_chart Modern Pharmacology

Oral absorption of metallic mercury is poor (< 0.01%)，但代謝氧化為Hg²⁺ is lipophilic, remains in nerve cells and bone marrow; has a long half-life and accumulates. High doses or prolonged use can cause mercury poisoning.

1. Acute poisoning leads to acute corrosive gastroenteritis, necrotic nephropathy, peripheral circulatory failure, a metallic taste and spicy sensation in the mouth, red and swollen mucous membranes, thirst, vomiting, abdominal pain, diarrhea, mucus or bloody stools, oliguria, dyspnea, collapse or toxic nephropathy, and even death.
2. Chronic poisoning mainly includes oral lesions, digestive system lesions, and neuropsychiatric symptoms. Initially, there is a metallic taste in the mouth, gum soreness, and increased salivation. In severe cases, oral mucous membranes become congested and ulcerated, gums swell, become loose and bleed, teeth fall out, and a black mercury line appears on the gums. Patients experience nausea, vomiting, loss of appetite, abdominal pain, and diarrhea. Psychologically, there is initial neurasthenia, followed by irritability, restlessness, insomnia, and some patients experience numbness and abnormal sensations in the extremities (acrodynia), showing symptoms of multiple neuritis. Some develop mercury-induced tremors. Additionally, there is liver and kidney function damage and reduced sexual function.
3. Topical use of calomel can sometimes cause toxic epidermal necrolysis, characterized by diffuse redness and swelling of the skin, partial epidermal peeling, and blisters of varying sizes all over the body.

Treatment methods (the following are general literature-recommended methods for removing toxins, not necessarily clinically verified):

1. For acute poisoning, early gastric lavage with sodium bicarbonate solution is recommended, followed by drinking milk or egg white, and avoiding salt. Do not use saline for gastric lavage.
2. Detoxifying agent sodium dimercaptopropanesulfonate (Unithiol) is administered intramuscularly for a week, followed by the use of detoxifying agents; if necessary, oral D-penicillamine or succimer metal chelators are used for mercury removal a month later.
3. Pay attention to correcting typical edema, electrolyte and acid-base imbalances, and actively prevent and treat secondary infections, shock, and renal failure.
4. For skin damage, a 3~5% sodium thiosulfate solution can be used for wet compresses; in cases of severe dermatitis, adrenal corticosteroids can be used.
5. Chinese medicinal detoxification uses the compound formula Glabrous Greenbrier Decoction, which has a slow mercury-removing effect and can improve symptoms. Glabrous Greenbrier 30g, Lonicera 30g, Prepared Rehmannia Root 24g, Morinda 5g, Cornus 5g, Moutan 5g, Carthamus 5g, Peach Kernel 10g, Alisma 10g, Cluster Mallow Fruit 30g, Bupleurum 10g, Liquorice Root 15g, decocted with water and taken.