Asafoetida is the dried latex exuded from the rhizome or tap root of several species of Ferula, perennial herbs of the carrot family. It is produced in Iran, Afghanistan, Central Asia, northern India, and Northwest China (Xinjiang). Different regions have different botanical sources.

Ferula is a genus of about 220 species of flowering plants in the family Apiaceae, native to the Mediterranean region east to central Asia, mostly growing in arid climates. They are herbaceous perennial plants growing to 1–4 m tall, with stout, hollow, somewhat succulent stems. The leaves are tripinnate or even more finely divided, with a stout basal sheath clasping the stem. The basal sheaths of Ferula oopoda are up to six inches (15 cm) long and form a cup holding about a cup of rainwater, possibly to draw pollinators in an arid land. The flowers are usually yellow, rarely white, produced in large umbels. Many plants of this genus, especially F. communis, are referred to as "giant fennel," although they are not fennel in the strict sense.