Hing or Heeng are the Hindi word for Asafetida, which has also been known as 'Devil's Dung' and "Stinking Gum'! This dark-brown, resin-like substance has a distinctive, sharp, pungent smell when raw but is extremely fragrant when added to hot oil or ghee (clarified butter) to temper a dish) or into a cooked/ cooking dish.
In Indian cooking, it is used largely for its digestive properties. It is added to foods that are thought to be 'gaseous' or gas-producing in nature, to make them easier to digest... foods like daals and beans for example. In India, Hing or Heeng can be bought in the form of small lumps or as a powder.