Mehndi is the application of Henna as a temporary form of skin decoration which is popular in South Asia, the Middle East, North Africa and Somalia. Mehndi decorations became fashionable in the West in the late 1990s, where they are sometimes called henna tattoos. Henna is typically applied during special occasions like weddings and festivals. It is usually drawn on the palms and feet, where the color will be darkest because the skin contains higher levels of keratin which binds temporarily to lawsone, the colorant of henna. Henna was used as a form of decoration mainly for brides.

The patterns of mehndi are typically quite intricate and predominantly applied to brides before wedding ceremonies. However, traditions in India, Bangladesh and Sudan sometimes expect bridegrooms to be painted as well. In Rajasthan (north-west India), where mehndi is a very ancient folk art, the grooms are given designs that are often as elaborate as those for brides.