Pick only on a fine day, when the sun has dried off the dew. The fresh juice affords 30 per cent, the dried herb 3 per cent of nitrate of potash. The stems and leaves supply much saline mucilage, which when boiled and cooked likewise deposits nitre and common salt. It is to these saline qualities that the wholesome invigorating properties of Borage are supposed to be due. Owing to the presence of nitrate of potash when burnt, it will emit sparks with a slight explosive sound.
Borage is much usedin France for fevers and pulmonary complaints.
By virtue of its saline constituents, it promotes the activity of the kidneys and for this reason is employed to carry off feverish catarrhs. Its demulcent qualities are due to the mucilage contained in the whole plant. For internal use, an infusion is made of 1 OZ of leaves to 1 pint of boiling water, taken in wineglassful doses. Externally, it is employed as a poultice for inflammatory swellings. The juice in syrup was thought not only to be good in fevers, but to be a remedy for jaundice, itch and ringworm.