Gum Ammoniacum, AmonGum, Amen Gum
It is a gum-resin exuded from the stem of a perennial herb of the umbel family. The plant grows to the height of around 8 or 9 ft., and its whole stem is pervaded with a milky juice, which oozes out on an incision being made at any part. This juice quickly hardens into round tears. "Lump ammoniacum," the other form in which the substance is met with, consists of aggregations of tears, frequently incorporating fragments of the plant itself, as well as other foreign bodies.
Ammoniacum has an unpleasant odor, which becomes more distinct on heating; externally it possesses a reddish-yellow appearance, and when the tears or lumps are freshly fractured they exhibit a waxy luster. It is mainly collected in Iran.
Taken internally, it acts by facilitating expectoration and is of value in chronic bronchitis. The resin has a mild diuretic action. It is antispasmodic and stimulant and is given sometimes as a diaphoretic and emmenagogue, used as a plaster for white swellings of the joints and also for indolent tumours. Its use is of great antiquity and is mentioned by Hippocrates.