Hemp, (Cannabis sativa), also called industrial hemp, plant of the family Cannabaceae cultivated for its fibre (bast fibre) or its edible seeds. Hemp is sometimes confused with the cannabis plants that serve as sources of the drug marijuana and the drug preparation hashish. Although all three products—hemp, marijuana, and hashish contain tetrahydrocannabinol (THC), a compound that produces psychoactive effects in humans, the variety of cannabis cultivated for hemp has only small amounts of THC relative to that grown for the production of marijuana or hashish.

The hemp plant is a stout, aromatic, erect annual herb. The slender canelike stalks are hollow except at the tip and base. The leaves are compound with palmate shape, and the flowers are small and greenish yellow. Seed-producing flowers form elongate, spikelike clusters growing on the pistillate, or female, plants. Pollen-producing flowers form many-branched clusters on staminate, or male, plants.