Asafoetida, Ferula asafoetida (family Umbelliferae), is a resin gum which comes from the dried sap from the stem and roots of the wild fennel genus Ferula. The resin is greyish-white when fresh, but dries to a dark amber colour. Chunks of asafoetida resin are too hard to be grated easily, and traditionally crushed between stones or with a hammer. Today, the most commonly available form is compounded asafoetida, a fine powder containing 30% asafoetida resin, along with rice flour and gum arabic.

It derives its English and scientific name from the Persian word for resin (asa) and Latin foetida, which refers to its strong sulfurous odor. Its pungent odour has resulted in its being called by many unpleasant names; thus the French know it, amongst other names, as Merde du Diable (Devil's faeces); in some dialects of English too it was known as Devil's Dung, and equivalent names can be found in German - Teufels Dreck, Danish - Dyvelsdræk, Dutch - Duivelsdrek, Icelandic - Djöflatað, Norwegian - Dyvelsdrekk, Swedish Dyvelsträck. In Turkish, it is known as Şeytantersi, Şeytan bökösu or Şeytanotu (the Devil's Herb).

In many of the northern Indian languages (Hindi, Urdu, Gujarati, Punjabi, Marathi, Bengali) it is known as hing. In Tamil, it is known as perungaayam. This spice is used as a digestive aid and in pickles. Its odour is so strong that it must be stored in airtight containers; otherwise, it spoils other foodstuffs. It loses its smell in cooking, however, and presents an onion-like taste. In India, it is used especially by the Brahmin caste of the Hindus and by adherents of Jainism, who are not allowed to eat onions. It is mainly grown in Iran, Afghanistan and Kashmir.

It has certain medicinal uses: it aids the digestion, and is helpful in cases of asthma and bronchitis. In the Appalachian region of the United States, it was used as a folk remedy for children's colds: it is mixed into a foul-smelling paste and hung in a bag around the afflicted child's neck.