Myrrh is a sap-like substance (resin) that comes out of cuts in the bark of trees that are members of the Commiphora species. Commiphora mukul, a related species, is not a source of myrrh. Myrrh is used to make medicine.
Myrrh is used for indigestion, ulcers, colds, cough, asthma, lung congestion, arthritis pain, cancer, leprosy, spasms, and syphilis. It is also used as a stimulant and to increase menstrual flow.
Myrrh is applied directly to the mouth for soreness and swelling, inflamed gums (gingivitis), loose teeth, canker sores, bad breath, and chapped lips. It is also used topically for hemorrhoids, bedsores, wounds, abrasions, and boils.
In foods and beverages, myrrh is used as a flavoring component.
In manufacturing, myrrh is used as a fragrance, in incense, and as a fixative in cosmetics. It is also used in embalming.
How does it work?
Myrrh can help decrease swelling (inflammation) and kill bacteria.
Funny, that latter sounds like "abortifacient," since there is no therapeutic reason to "increase menstrual flow."