The betel (Piper betle) is the leaf of a vine belonging to the Piperaceae family, which includes pepper and kava. It is valued both as a mild stimulant and for its medicinal properties. Betel leaf is mostly consumed in Asia, and elsewhere in the world by some Asian emigrants, as betel quid or in paan, with or without tobacco, in an addictive psychostimulating and euphoria-inducing formulation with adverse health effects. Betel is notable for staining the teeth of regular users.

Paan ( पान from Sanskrit parṇa, "leaf") is a preparation combining betel leaf with areca nut and sometimes also with tobacco. It is chewed for its stimulant and psychoactive effects. After chewing it is either spat out or swallowed. Paan has many variations. Slaked lime (chunnam) paste is commonly added to bind the leaves. Some South Asian preparations include katha paste or mukhwas to freshen the breath.