A wax ring is used to connect your toilet to the floor flange and drain pipe. Proper installation of the wax ring results in its compression between the horn on the bottom of the toilet and the floor flange. The compression of the wax creates a water and odor seal that can last for the life of the toilet. Improper installation of the wax ring or other failure of the wax ring can result in leakage and odor escaping the sealed environment. If your floor flange is not at or above the finished floor the wax ring may not compress enough to create a tight long lasting seal resulting in eventual failure.
Has your wax ring started to or already failed? If you are replacing it you may want to consider upgrading your toilet to one with a cleaner, more powerful flush or perhaps a toilet that can help you use less water.