Can you tell me is ranch dressing actually gluten-free, safe for celiac?

Depends on the brand: Always check the label of products you use and call the company if you are not sure. Newman's own is a very good company about labeling gluten free dressings including ranch. Many other companies offer either item free or at least no gluten ingredients like ken's, hidden valley and kraft. But unfortunatly, it's important to check to be sure the formulation of the product hasn't changed.