Mastic is a RESIN that is derived from the mastic tree, which is native to the Mediterranean region. It is a natural gum that has been used for centuries as a sealant and adhesive in construction and other applications. It is also used in cosmetics, pharmaceuticals, and food products. Mastic has a strong, resinous smell and is often used in perfumes and incense. It is also used in traditional medicine to treat various ailments.