Properties: Bitter, salty, warm (some sources say Cold).

Meridans Entered:
Primary: Heart, Lung, Spleen

1. Breaks up stagnation, disperses swelling, expels pathogens and resolves Toxicity
   Hot and cold Sudden Turmoil (霍亂 Huo Luan) with fever, abdominal swelling and pain, vomiting and diarrhoea
   Black jaundice during labour due to Liver and Kidney deficiency with Blood Stasis and internal obstruction
   Discharge from sexually transmitted diseases
   Obstructed urination from Blood, Heat, Qi, and stones
   Constipation, red and white dysentery, intestinal Wind, turbid Toxicity
   Swollen, red and painful eyes, headache, hypertension
   Swollen, obstructed sore throat, toothache
   Boils and carbuncles, scrofula
2. Frees the flow of Heart Qi
   Placed under the tongue for acute heart pains with cold hands and feet (saliva will convert to nitrite)
3. Aids fasting
   Mentioned in the Shen Nong Ben Cao Jing as part of the superior class of minerals which can, with protracted taking, make the body light. This may suggest it was part of supplementing the diet when engaging in an "avoiding grain" (Bigu 辟穀) fasting regime to cultivate life (Yangsheng 養生).

Suggested Daily Dosage: 1.5 to 3g internally as pills or powder, or grind into powder and blow into the throat, or insert a pellet the size of a millet grain into the inner canthus of the eye overnight and wash out the next morning, or apply to wounds with water or saliva.

Cautions: Traditionally avoid use during pregnancy or in deficiency conditions. Do not combine with bitter, cooling herbs such as Ku Shen, Xing Ren, Dan Zhu Ye, bitter vegetables or porridge.

It is non-combustible but accelerates the burning of other combustible materials so should be used with caution if mixed, especially with sulphur. If exposed to prolonged heat it may explode.

1. Potassium nitrate
   Water soluble crystalline salt that acts as a strong oxidiser

Notes:

Most indications have been taken from A+ Hospital with some additional information from Butler (2009).

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Most important use historically is its role in the creation of gunpowder by mixing with sulphur and carbon. It is thought to have first been discovered by Wei Boyang in 142 AD but was not fully described until Ge Hong in 300 AD (Carr, 2017).

Its ability to act as an accelerant made it take on important symbolic qualities for European alchemy where it was more likely to be the Salt of the "Three Primes" of Paracelsus than regular table salt.

Potassium Nitrate is still used today as plant fertiliser, for curing certain meats, in toothpastes, medicines and other uses.

It can also be reacted with sulphuric acid to form nitric acid (NileRed, 2016a), called Aqua Fortis by ancient alchemists. This then reacts with mercury to form mercury nitrate (NileRed, 2016b) which was used by hatters for felting and led to their reputation for eccentricity.