Luffa is a genus of tropical and subtropical vines in the cucumber (Cucurbitaceae) family.In everyday non-technical usage, the luffa, also spelled loofah, usually means the fruit of the two species L. aegyptiaca and L. acutangula. The fruit of these species is cultivated and eaten as a vegetable. The fruit must be harvested at a young stage of development to be edible. The vegetable is popular in China and Vietnam. When the fruit is fully ripened it is very fibrous.