Mastic (Pistacia lentiscus) is an evergreen shrub or small tree growing to 3-4 m tall, mainly cultivated for its aromatic resin on the Greek island of Chios. It is native throughout the Mediterranean region, from Morocco and Iberia at the east through southern France and Turkey to Syria and Israel in the west; it is also native on the Canary Islands. The word mastic derives either from a Phoenician word or from the Greek verb mastichein ("to gnash the teeth", origin of the English word masticate) or massein ("to chew").
Mastic gum is principally used either as a flavouring or for its gum properties, as in mastic chewing gum. Chios's native drinks, Mastichato, a smooth sweet smelling mastic liqueur and mastic-flavored ouzo, are made from "Chios Tears". In culinary uses, it can also be enjoyed in baking and in sweets such as biscuits, mastic ice cream, and mastic spoon sweets. In its refined form it is also used as the primary ingredient for toothpaste, shampoos and perfumes.
People in the Mediterranean region have used mastic as a medicine for gastrointestinal ailments for several thousand years. The first century Greek physician and botanist Dioscorides wrote about the medicinal properties of mastic in his classic treatise De Materia Medica ("About Medical Substances"). Some centuries later by Markellos Empeirikos and Pavlos Eginitis also noticed the effect of mastic in the digestive system.