Sauvarchala lavana, also known as Kala Namak or black salt, is a type of salt primarily used in Ayurvedic treatments .
 

•  Composition: It's composed mainly of Sodium Chloride, with traces of iron, sodium sulphide, sodium bisulfate, sodium bisulfite, and hydrogen sulfide. 
•  Ayurvedic Properties: Sauvarchala lavana is described in Ayurveda as being Sukshma (minute), Ushna Virya (hot potency), and Laghu (light to digest)

Uses & Benefits:
 

• It enhances food taste and promotes heart health. 
• It aids digestion by stimulating digestive fire and balancing acid production. 
• It's used to treat digestive ailments like constipation, colic pain, abdominal tumors, bloating, and intestinal worms. 
• It's also used to increase haemoglobin levels and treat anaemia due to its iron content. 
•  Important Note: While beneficial, excessive consumption of Sauvarchala lavana can increase Pitta and Kapha doshas, according to Ayurveda. It's generally recommended to limit intake to less than 6 grams per day. 
•  Sauvarchala lavana finds its use in several Ayurvedic formulations, including Chandraprabha Vati, Chitrakadi Vati, Agnitundi Vati, and Pradarantak Lauh.