Blue cheese dressing is a popular side sauce, salad dressing and dip in the United States. It is usually made of some combination of blue cheese, mayonnaise, and buttermilk, sour cream or yogurt, milk, vinegar, onion powder, and garlic powder. There is a blue cheese vinaigrette that consists of salad oil, blue cheese, vinegar, and sometimes seasonings. Most major salad dressing producers and restaurants in the United States produce a variant of blue cheese dressing. It is commonly served as a dip with Buffalo wings or crudités (raw vegetables).