The Rif or Riff (Berber: ⴰⵔⵔⵉⴼ Arrif, Arabic: الريف Al-Rif) is a mainly mountainous cultural region in the northern part of the Kingdom of Morocco. The Rif has some fertile plains and stretches from Cape Spartel and Tangier in the west to Berkane and the Melwiyya River in the east and from the Mediterranean in the north to the Ouergha River in the south. It is separated into Eastern Rif (Al Hoceima, Driouch, Nador, Berkane) and Western Rif (Tanger, Tetouan, Chefchaouen, Taounate).
The Balsam of Matariyya was a substance famous as a panacea among physicians in the Middle East and Europe during the Antique and Medieval periods. The substance has long been used as a medicine, with early references to the substance recorded as far back as 285 BC. The Balsam of Matariyya was said to be derived from an Egyptian plant and is sometimes also referred to as the balm of Gilead or the balm of Mecca.
Some balsams, such as Balsam of Peru, may be associated with allergies. In particular, Euphorbia latex ("wolf's milk") is strongly irritant and is cytotoxic.
Balsam is a solution of plant-specific resins in plant-specific solvents (essential oils). Such resins can include resin acids, esters, or alcohols. The exudate is a mobile to highly viscous liquid and often contains crystallized resin particles. Over time and as a result of other influences the exudate loses its liquidizing components or gets chemically converted into a solid material (i.e. by autoxidation).Some authors require balsams to contain benzoic or cinnamic acid or their esters. Plant resins are sometimes classified according to other plant constituents in the mixture, for example as: