The primary ingredient used in traditional Greek tzatziki sauce is yogurt. Typically made from strained Greek yogurt, tzatziki is a refreshing sauce often served as a dip or accompaniment to various dishes, especially grilled meats or pita bread. The yogurt provides a creamy texture and tangy flavor, which is complemented by ingredients like cucumber, garlic, olive oil, and herbs such as dill or mint. Tzatziki is not only delicious but also versatile, as it can be used in a variety of culinary applications, highlighting the importance of yogurt in Mediterranean cuisine.