Asafoetida is the dried resin extracted from a particular species of herb. The species is native to the deserts of Iran, mountains of Afghanistan, and is mainly cultivated in India. Asafoetida is a very smelly spice, but in cooked dishes it delivers a flavor similar to leeks.
Asafoetida is used as a digestive aid, in food as a condiment, and in pickle. It typically works as a flavor enhancer and, used along with turmeric, is a standard component of Indian cuisine. When making a lentil curry (dal) and many other vegetable dishes, the flavour is often enhanced with a tempering (quick fry) of asafoetida together with other spices.
It is especially widely used in South Indian and Maharashtrian (Mumbai) cuisine, which is mainly vegetarian. It is often used to harmonize sweet, sour, salty and spicy components in food.