From McDonalds.com:
McChicken Sauce - Vegetable oil (canola and/or soybean and/or corn oil), water, glucose, egg yolk, white vinegar, salt, spices, xanthan gum, sodium benzoate, calcium disodium EDTA.
Sounds like "McMayo" to me...but my friend tells me that the manager makes the "special" sauce in back himself
