When a tree's wound penetrates through the bark and into the sapwood, the tree bleeds a resin. Myrrh gum, like frankincense, is such a resin. When people harvest myrrh, they wound the trees repeatedly to bleed them of the gum. Myrrh gum is waxy and coagulates quickly. After the harvest, the gum becomes hard and glossy. The gum is yellowish and may be either clear or opaque. It darkens deeply as it ages, and white streaks emerge.
Myrrh gum is commonly harvested from the species Commiphora myrrha. Another commonly used name, Commiphora molmol, is now considered a synonym of Commiphora myrrha. Commiphora myrrha is native to parts of Saudi Arabia, Oman, Yemen, Somalia, Eritrea and eastern Ethiopia. Meetiga, the trade-name of Arabian Myrrh, is more brittle and gummy than the Somali variety and does not have the latter's white markings. Liquid myrrh, or stacte, written about by Pliny, was an ingredient of Jewish holy incense, and was formerly greatly valued but cannot now be identified in today's markets.
The oleo gum resins of a number of other Commiphora species are also used as perfumes, medicines, and incense ingredients. These myrrh-like resins are known as opopanax, balsam, bdellium, guggul bisabol, and Indian myrrh. In pharmacy, myrrh is used as an antiseptic in mouthwashes, gargles, and toothpastes. It is also used in some linaments and healing salves that may be applied to abrasions and other minor skin ailments. Myrrh has also been recommended as an analgesic for toothaches and can be used in linament for bruises, aches, and sprains. Myrrh gum is commonly claimed to remedy indigestion, ulcers, colds, cough, asthma, lung congestion, arthritis pain, and cancer.