What is the compound that gives garlic its pungent flavor?

When garlic is crushed or chopped, an enzyme called alliinase is released, which converts alliin into allicin. Allicin is the compound that gives garlic its strong, characteristic odor and flavor.

It's important to note that allicin is unstable and quickly breaks down into other sulfur-containing compounds, which contribute to garlic's complex flavor profile.