The two can easily be confused but the first thing to know if that tzatziki is a Greek condiment while raita is an Indian condiment. While tzatziki is made of whole milk strained yogurt, raita is generally a bit thinner made with regular whole milk yogurt (not strained). Raita is also made with a variety of chopped vegetables which can include cucumber, eggplant, potatoes or spinach and can also include tomatoes or bananas. Tzatziki is a bit simpler made with just shredded or diced cucumber. And finally, the seasonings are quite different. Raitas are seasoned with black mustard seeds, garam masala and a handful of fresh herbs such as cilantro, tarragon, chervil, dill and mint. Most tzatziki recipes only use the latter two.