Ammoniacum, a gum-resin exuding from Dorema Ammoniacum, and D. Aucheri, perennial, umbelliferous plants, natives of Irak, in Persia, whence the gum is shipped, via Bombay. It is reddish yellow, opalescent and slightly foetid, and is used as a substitute for the allied assafoetida, in plasters for tumours, and as an expectorant. African ammoniacum, used for fumigation, is obtained from Ferula tingitana, a native of Morocco. It is said to be anti-spasmodic in its action, but is chiefly used to check secretion in chronic bronchitis. In the form of a plaster it is also employed externally to relieve inflamed joints.