Hing, also known as asafoetida, is a resinous spice extracted from the roots of the Ferula assa-foetida plant. It's a pungent spice with a strong, onion-like aroma, and it's a staple in Indian cuisine, particularly in vegetarian cooking. Hing is used as a flavoring agent, and it's also known for its potential health benefits, including aiding digestion.