Cubeb (Piper cubeba), or tailed pepper, is a plant in genus Piper, cultivated for its fruit and essential oil. It is mostly grown in Java and Sumatra, hence sometimes called Java pepper. The fruits are gathered before they are ripe, and carefully dried. Commercial cubebs consist of the dried berries, similar in appearance to black pepper, but with stalks attached — the "tails" in "tailed pepper". The dried pericarp is wrinkled, its color ranges from grayish-brown to black.

The herb has often been associated with the reproductive system and has been used to treat cystitis, leukorrhea, urethritis and prostate infections, and has often been used in the treatment of gonorrhea. Cubeb Berry has been shown to be effective in easing the symptoms of chronic bronchitis and has also been used for digestive ailments. The herb is believed to be effective in treating dysentery. Cubeb Berry also has a local stimulating effect on the mucous membranes of the urinary and respiratory tracts.

The dried fruits contain up to 10% essential oil composed of monoterpenes ( sabinene 50% , carene, ± -thujene, 1, 4-cineol and 1, 8-cineol) and sesquiterpenes ( copaene, ± - and ² -cubebene, ´ -cadinene, caryophyllene, germacrene, cubebol) .

The monoterpenes dominate by mass, but the sesquiterpenes are important for the characteristic flavour. The pungency is caused by the lignane cubebin ( 2% ) and several related compounds: hinokinin, clusin, dihydroclusin, dihydrocubebin and more. Cubeb is used in local Indonesian cookery, especially in Indonesian gulé s ( curries) .

It was once popular in Arab cooking. Because of its aromatic qualities, cubeb would go well with meat, cheese and vegetable dishes. Cubeb and its oil are carminative, diuretic, stimulant and antiseptic and were employed as genito-urinary antiseptics and especially for clearing up gonorrhea. Extract of cubeb is also expectorant, being helpful in pulmonary infections such as bronchitis.