Hing comes from the resin of giant fennel plants that grow wild in Afghanistan and Iran. The resin can be kept pure, but in the States, you mostly find it ground to a powder and mixed with wheat.
It has been shown to be a good source of antioxidants. While limited research suggests multiple benefits — particularly for digestive health — much more human research is needed. Still, when ground into a powder, this ingredient — also known as hing — makes a great addition to your spice cabinet.