Hydrated calcium sulphate.  Ca SO4.2H2O   Shí gāo   Gypsum (Mineral)  
Nature: extremely Cold, very Cold      FLAVOR: Biting, yet pleasant, acrid, sweet  CHANNEL: Stomach, Lung
FUNCTIONS
GROUP: Clearing Internal Heat- Reducing Fire.
1. Clear internal heat and reduce Fire.[1,2,3,4,5] Quench thirst.[1,2,3,4]  Relieving restlessness. Clears fevers.[1] Dispersing discomfort in chest.[4] Clears excessive Heat from the Lungs.[5]
2. Promoting regeneration of the tissue and wound healing- Forging- External use.[2]
ACTIONS INDICATIONS
1. Acute febrile diseases with pathogenic factors at the Qi level:[4,5] shown as high fever without chills, dysphoria, thirst, irritability, profuse sweating.[4] P- full, flooding, big. T- yellow coat and red body, and other Heat symptoms of excess type. Headache, and restlessness. Dry mouth.[4] Great thirst.[4]. delirium.[1] Meningitis;[4] High fever.
2. Lung Heat- Showing as wheezing and coughing, hemoptysis and sore throat.[1,5] Asthma, shortness of breath, vexation and thirst. Thick, viscous sputum.[5]
3. Stomach Heat: Gum bleeding, gingivitis.[4] Headache, toothache,[4,5] swollen and painful gums.[5]
4. External usage- For slow healing ulcerated sores, eczema, burns and scalds.[5] Usually applied topically in powdered form after being calcined and mixed with other herbs.[4] May also be taken internally for these conditions.[4]
CONTRAINDICATIONS: Cold syndromes of deficiency type in the Spleen and Stomach and Interior Heat syndrome due to Yin deficiency.[3,5] Used only in full hot conditions. Chronic illnesses or if the body is weak- it damages the true Qi. If its usage is essential, it must be combined with Ren shen or Dang shen.[4] Yang deficiency.[5]
PATENT COMBINATIONS
- Lung attacked by Warm-Dryness:
Releases external dryness, moistens the Lung and nourishes the Lung Yin. Tonifies Qi and alleviates coughing Eriobotrya & Ophiopogon Combination- Qing zao jiu fei tang.
COMBINATIONS
PREPARATIONS: Mineral. This substance should be broken up and cooked for 20-30 minutes before the other herbs are added.[5] Decocted in water prior to other drugs 15-60 g.[2,3] Appropriate dosage for external use. For clearing away Heat and purging fire, it should be used unprepared: for promoting regeneration of tissue and healing of wounds, it should be calcined.[3] Good quality is white and fibrous.[5]
Decoction 9-30 g.[1,5] 20-30 g.[4] Up to 90 g for very high fevers.[5]

References
Inner Path can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Research

Effect on temperature regulation: Oral administration of decoctions of Gypsum did not show any significant antipyretic effect in rabbits or dogs.[1]
Antibiotic effect: In vritro experiments have demonstrated no inhibitory effect agains major pathogenic bacteria from decoctions of Gypsum.[1]
References
[1] Chinese Herbal Medicine Materia Medica- Dan Bensky and Andrew Gamble- Eastland Press 1986 Seattle Washington ISBN 0-939616-15-7