Cannabis. Computer artwork of the leaf of the hemp or marijuana plant, Cannabis sativa. This plant is used as an intoxicating drug. Native to central Asia it is cultivated for three products: fibre from the stems, seed oil, and the drug. The active ingredient of the drug is a resin from glandular hairs on the leaves, stems and flowers. The plant is a fast-growing annual and a common weed in northern India. In good conditions it can grow to over five metres tall. Male and female flowers are borne on different plants, the females being the most potent as the drug is most concentrated in them.