Watermelon Frost is the name of a traditional Chinese medicinal material. It is produced by processing the mature, fresh fruits and rinds of the watermelon (Citrullus lanatus (Thunb.) Matsumu. et Nakai), a plant of the Cucurbitaceae family, with sodium nitrate. It has the effects of clearing heat, purging fire, reducing swelling, and relieving pain. It is primarily used to treat sore throat, laryngeal obstruction, and mouth ulcers.
Watermelon Frost
Watermelon Frost is the name of a traditional Chinese medicinal material. It is produced by processing the mature, fresh fruits and rinds of the watermelon (Citrullus lanatus (Thunb.) Matsumu. et Nakai), a plant of the Cucurbitaceae family, with sodium nitrate. It has the effects of clearing heat, purging fire, reducing swelling, and relieving pain. It is primarily used to treat sore throat, laryngeal obstruction, and mouth ulcers.
Chinese Name : 西瓜霜
Latin Name : Mirabilitum Praeparatum
Aliases : Watermelon White Frost, Watermelon Nitrate
Nature, Flavor & Meridian Tropism : Salty in taste, cold in nature; enters the Lung, Stomach, and Large Intestine meridians
Benefits & Efficacy
Benefits
Clears heat, purges fire, reduces swelling, and relieves pain.
Indications
Sore throat, laryngeal obstruction, mouth ulcers.
Usage and Dosage
1. Oral use: 0.5–1.5 g. 2. Topical use: Apply an appropriate amount; grind into a powder and apply to the affected area.
Precautions
Patients requiring treatment with traditional Chinese medicine should first consult a licensed TCM hospital, where a TCM practitioner will conduct a professional pattern differentiation and issue a prescription.
Chemical Constituents
It primarily contains sodium sulfate, as well as stevioside, citric acid, and other compounds.
Pharmacological Actions
Modern pharmacological research suggests that Watermelon Frost has antibacterial, anti-inflammatory, and local analgesic effects.
Relevant Discussions
1. *Comprehensive Treatise on the Treatment of Ulcers*: “Treats conditions of the throat, mouth, and teeth, including laryngeal obstruction.”
2. *Revised Materia Medica*: “Treats laryngeal obstruction and chronic cough.”
Applications
Clinical Applications
1. For all throat conditions, including swelling, pain, and white discharge, to reduce inflammation and swelling: 5 qian of watermelon frost, 5 qian of Xiyue Stone, 6 fen of fly cinnabar, 5 fen of dried silkworm, and 5 fen of borneol. Grind into an extremely fine powder and blow onto the affected area. Contraindicated for diaphonic diphtheria. (*Outline of the Treatment of Throat Disorders* by Yu Yueshi)
2. For diphtheria: 2 liang of watermelon frost, 1 qian of calcined Ren Zhong Bai, 2 qian of cinnabar, 2 fen of male deer antler essence, and 1 qian of borneol. Grind all ingredients into a fine powder, then mix until smooth and homogeneous. If the condition is not diphtheria, omit the male deer antler essence. (Gua Shuang San, from *Essentials for Treating Throat Disorders*)
Related Compatibility
Watermelon Frost Combined with Borneol: Watermelon Frost excels at clearing heat, purging fire, reducing swelling, and relieving pain; borneol excels at clearing heat, relieving pain, reducing swelling, and promoting tissue regeneration. When these two herbs are combined, their effects of clearing heat, purging fire, reducing swelling, relieving pain, and soothing the throat are enhanced. This formulation is suitable for sore throat and mouth ulcers caused by internal heat toxins.
Related Medicines
Watermelon Frost Throat-Soothing Tablets, Zhu Huang Throat-Blowing Powder, Guilin Watermelon Frost (capsules, lozenges), and Guashuang Fever-Reducing Capsules.
Related Prescriptions
Jade Key (from *Outline of the Treatment of Throat Aphthous Ulcers*).
Notes
References: 1. *Clinical Guidelines for Medicinal Use of the Pharmacopoeia of the People’s Republic of China: Volume on Crude Chinese Herbal Slices, 2020 Edition* 2. *Pharmacopoeia of the People’s Republic of China, 2020 Edition* 3. *Comprehensive Dictionary of Traditional Chinese Medicine* 4. *Chinese Materia Medica*
Processing & Preparation
Harvesting & Processing
Harvest ripe fruits in summer; they are generally used fresh.
Processing Methods
1. Select watermelons that are not yet fully ripe, remove the rind, and cut it into small pieces. For every 10 jin of rind, add 15 jin of potassium nitrate, mix thoroughly, and place the mixture into a yellow sand jar. First, line the bottom of the jar with a layer of watermelon rind as a base. Once the jar is filled with the mixture of rind and potassium nitrate, cover it with another layer of watermelon rind until it is completely buried. Seal the jar and place it in a well-ventilated area.After several days, a white powdery frost will begin to form continuously on the outside of the yellow sand jar. Gently brush off the frost until it no longer forms. Remove any sand particles from the collected white frost to obtain pure watermelon frost.
2. Select a watermelon weighing about 6–7 jin. Cut it open at the stem end and scoop out some of the flesh. Fill the melon with 1 jin (or slightly more) of saltpeter-treated rind. Then cover it with the cut-off rind, secure it with bamboo skewers, and hang it in a cool, well-ventilated place. After about 10 days, a white powder will continuously form on the outside of the rind; simply brush it off as it appears.
Storage Methods
Store in a lime jar or seal in a porcelain bottle, keeping it in a cool, dry place away from moisture and heat.
Crude Drug Identification
Properties of Crude Drugs
This product is an off-white to yellowish-white crystalline powder. It has a faint odor and a salty taste.
Properties of Processed Slices
See “Characteristics of Medicinal Materials.”
Botanical Information
Botanical Classification
Derived from the watermelon (Cucumis sativus), a plant of the Cucurbitaceae family.
Morphological Characteristics
It is an annual, vine-like herb. The stems are slender and weak, creeping, with distinct ridges and grooves.Tendrils are dichotomous and hairy; leaves are triangular-ovate or broadly ovate, 8–20 cm long and 5–18 cm wide, deeply 3-lobed or nearly 3-lobed, with the central lobe longer than the lateral lobes; the lobes are further irregularly pinnately divided. Both surfaces are pale green, with wavy or sparsely toothed margins.The plant is monoecious; both male and female flowers are solitary in the leaf axils. Male flowers are 2–2.5 cm in diameter, with slender pedicels covered with long soft hairs;the calyx is fused into a broad bell shape, covered with long hairs, and 5-lobed at the apex, with lobes that are narrowly lanceolate or linear-lanceolate; the corolla is fused into a funnel shape, green on the outside, covered with long soft hairs, and deeply 5-lobed at the upper part, with lobes that are ovate-elliptic or broadly elliptic and blunt at the apex; there are 5 stamens, of which 4 are fused in pairs and 1 is free, with short, thick filaments;The female flowers are larger than the male flowers and resemble them in appearance; the ovary is inferior, ovate, and more or less covered with short soft hairs on the outside; the style is short, and the stigma is shallowly 5-lobed; the gourd-like fruit is nearly round or oblong, about 30 cm in diameter, with a green or dark green surface, often bearing alternating light and dark stripes.The seeds are numerous, flattened, slightly ovate, black, red, white, or yellow—sometimes mottled—with smooth surfaces on both sides, an ovate base, and often slightly arched margins. Flowering and fruiting occur in summer.
Distribution Area
It is cultivated throughout China.
Growth Habits
It prefers a warm climate. It is heat-tolerant, intolerant of low temperatures, drought-tolerant, and sun-loving. It adapts to a wide range of soil types, but is best grown in alluvial soil along riverbanks and sandy loam with a deep topsoil layer.
Propagation Methods
Propagated by seed, either by direct seeding or by raising seedlings for transplanting.
Cultivation Techniques
1. Direct Seeding Method: Sow in spring (March–April). After soaking, disinfecting, and pre-germinating the seeds, make holes with a row spacing of 2 m and a plant spacing of 0.4 m, and sow 4 seeds per hole. Apply base fertilizer before sowing; after sowing, cover the seeds with 2–3 cm of loosened soil. Thin the seedlings when they have 3–4 true leaves, selecting and retaining one healthy seedling per hole.
2. Seedling Transplanting Method: For spring planting in February–March, sow seeds treated as described above into nutrient-rich soil blocks or pots in a heated seedbed, planting 2 seeds per block (or pot). After germination, remove one of the weaker seedlings. When the seedlings have developed 3–4 true leaves, transplant them with the soil block or pot intact.