Luffa operculata (common name, sponge cucumber, wild loofa or mướp xơ in Vietnamese) is a species of Luffa. It is cultivated for its fruit, which when fully ripe is strongly fibrous and is used as a fibrous scrubbing sponge for household cleaning. The fruit is a capsule with spikes. The fruit is dark-brown when mature. It is also grown in gardens and yards as an ornamental plant. In colder places they can be grown indoors as a houseplant.