The toilet bowl connects to the toilet flange on the floor. To ensure a watertight seal, a wax ring is used between the toilet and the flange. The ring has a plastic flange that fits into the sewer line and a soft wax ring that seals against the underside of the toilet. Occasionally, the wax will pull away from the toilet and water may leak from under the bowl, after each flush.
Replacing the ring requires completely removing the toilet. Because the toilet is heavy, 50 pounds or more, it is best to work with an assistant. Start by turning off the water supply. Flush the toilet to drain it. Place a pan or towel under the tank and disconnect the water supply line from the tank. Remove the tank cover and put it out the way. The toilet is made of vitreous china, it can break easily and it can scratch other surfaces. So it is best to place pieces on a towel or cardboard and out of the work area.
If your tank and bowl are two pieces, it will be easier if you take them apart now. Remove the two or three bolts in the bottom of the tank that secure it to the bowl. With a helper, lift the tank off of the bowl and place it out of the way. Scoop out any remaining water from the bowl and remove the nut covers and nuts that secure the bowl to the bolts in the floor.
Lay out a thick towel or piece of cardboard on the floor on which to lay the toilet. With the assistance of a helper, lift the toilet off of the bolts and lay it on its side on the towel. Remove the old wax ring and scrape off any remaining wax and debris. Also remove any wax from the toilet flange on the floor.