Generally, traditionally made tortillas do not contain any products such as eggs or milk. Whilst eggs aren't vegan-friendly, milk isn't suitable for those who are lactose intolerant. It is worth looking at the ingredients in detail beforehand to confirm that they do not contain both or either of these ingredients. Some will use preservatives that contain other dairy products. Most are made using flour, salt, and ground maize and in some instances depending on the brand, they will be made using lard, though you may come across some that add products such as milk and butter to their recipes. Some brands use dairy ingredients to make their tortilla wraps. As mentioned, for guaranteed assurance that the tortillas do not contain eggs or milk you will need to read the ingredients listed on the packaging. Whilst it is easy to identify the listing of eggs or milk, other ingredients are not so easy to pinpoint.