Dioscoreas are herbaceous, climbing, vine-like plants, the tuber being totally buried or sometimes protruding from the ground. Tubers weigh upto 5 kg with 40- to 50-kg tubers being recorded in some species. Drug material is obtained from both wild and cultivated plants with plants collected from the wild having been exploited considerably more than cultivated ones. Commercial cultivation is less economic, requiring a 4- to 5-year growing period and some form of support for the climbing stems. Tubers are collected from 3 to 5-year-old plants (with maximum diosgenin and yamogenin content), when they are dormant by ploughing. They are thoroughly washed of adhering soil and transported appropriately for diosgenin isolation from fresh tubers. In India, the tubers are chopped into smaller units to dry in the sun and then packed. Exporters grade the material, which is to be ground to prepare powders or processed further to extract diosgenin or 16-dehydro pregnenolone (16-DPA) from it.